439 results on '"M. Król"'
Search Results
2. Inverted optical bistability and optical limiting in coherently driven exciton–polaritons
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M. Furman, A. Opala, M. Król, K. Tyszka, R. Mirek, M. Muszyński, B. Seredyński, W. Pacuski, J. Szczytko, M. Matuszewski, and B. Piętka
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Applied optics. Photonics ,TA1501-1820 - Abstract
Exciton–polaritons in optical cavities exhibit strong nonlinearities predominantly because of the third-order Kerr-like interactions mediated by the excitonic component. Under quasi-resonant excitation, depending on the energy of the incident laser, it results in the optical limiting or bistable behavior. The latter phenomenon is manifested by the hysteresis loop observed in the input–output power characteristics, when a cavity is quasi-resonantly driven by a laser field. The direction of the loop is typically counterclockwise when increasing and subsequently decreasing the optical power. In this work, we demonstrate the optical bistability with an inverted hysteresis direction. It is observed in an exfoliated CdTe-based semiconductor microcavity when the frequency of the pumping laser is tuned slightly below the lower polariton mode. This unusual behavior is caused by the interplay of the suppression of strong coupling and the redshift of the lower polariton mode energy when increasing the incident power. We show that under these conditions, the polariton microcavity can be used as an optical limiter. All of the experimental observations, the shape and the direction of the hysteresis and the optical limiting behavior, are fully supported by a theoretical model.
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- 2023
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3. Analysis of the Mechanical Properties of the Titanium Layer Obtained by the Mold Cavity Preparation Method
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A. Dulska, J. Szajnar, and M. Król
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modular insert ,titanium layer ,cast iron ,slm ,Mining engineering. Metallurgy ,TN1-997 ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
The article presents the technology of layered casting with the use of 3D printing to make a frame insert. The insert was made of powdered titanium and then filled with liquid cast iron. The paper presents the results of research, including structure observation and hardness measurements, as well as abrasion resistance tests. The results indicate the possibility of creating a local reinforcement using a frame insert. The resulting casting is characterized by a local increase in hardness and, in addition, an increase in abrasion resistance of the entire surface layer. The quality of the obtained connection depends strongly on the casting parameters.
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- 2020
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4. Influence of nitrogen supply on spring barley productivity and nitrate reductase activity
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U. Wojcieska, E. Wolska, and M. Król
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Agriculture (General) ,S1-972 - Abstract
The aim of the present study was to obtain some informations on the productivity of four chosen barley varieties growing at low and high nitrogen level. Some parameters of the yield structure and nitrate reductase activity were taken into consideration. It was found that there exist some differences in the yield between the compared varieties and some differences in their reaction to a high N level in the soil. The grain yield increase of the plants treated with high nitrogen doses was above all the result of the increase in dry matter of the lateral shoots and in leaf area. Distinct increase in the number of grains per ear and 1000-grains weight was also observed. The amount of reduced nitrogen collected during the growth season depended, in part, on the nitrate reductase activity and in part on the amount of the enzyme present in the plant. A rise of the nitrogen level caused an increase in nitrate reductase activity, in all varieties. The different influence of nitrogen on the growth of green organs in the compared varieties caused differences in the amount of the enzyme present in the plants and in protein yields.
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- 2013
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5. Energy-efficient neural network inference with microcavity exciton-polaritons.
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Michal Matuszewski, Andrzej Opala, R. Mirek, M. Furman, M. Król, K. Tyszka, Timothy C. H. Liew, Dario Ballarini, Daniele Sanvitto, Jacek Szczytko, and Barbara Pietka
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- 2021
6. Crystallization Process of Ultra-Light Mg-Li Alloys
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M. Król
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General Physics and Astronomy - Published
- 2022
7. Evaluating NOx stack plume emissions using a high-resolution atmospheric chemistry model and satellite-derived NO2 columns
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M. Krol, B. van Stratum, I. Anglou, and K. F. Boersma
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Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This paper presents large-eddy simulations with atmospheric chemistry of four large point sources world-wide, focusing on the evaluation of NOx (NO + NO2) emissions with the TROPOspheric Monitoring Instrument (TROPOMI). We implemented a condensed chemistry scheme to investigate how the emitted NOx (95 % as NO) is converted to NO2 in the plume. To use NOx as a proxy for CO2 emission, information about its atmospheric lifetime and the fraction of NOx present as NO2 is required. We find that the chemical evolution of the plumes depends strongly on the amount of NOx that is emitted, as well as on wind speed and direction. For large NOx emissions, the chemistry is pushed in a high-NOx chemical regime over a length of almost 100 km downwind of the stack location. Other plumes with lower NOx emissions show a fast transition to an intermediate-NOx chemical regime, with short NOx lifetimes. Simulated NO2 columns mostly agree within 20 % with TROPOMI, signalling that the emissions used in the model were approximately correct. However, variability in the simulations is large, making a one-to-one comparison difficult. We find that temporal wind speed variations should be accounted for in emission estimation methods. Moreover, results indicate that common assumptions about the NO2 lifetime (≈ 4 h) and NOx:NO2 ratios (≈ 1.3) in simplified methods that estimate emissions from NO2 satellite data need revision.
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- 2024
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8. A lightweight NO2-to-NOx conversion model for quantifying NOx emissions of point sources from NO2 satellite observations
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S. Meier, E. F. M. Koene, M. Krol, D. Brunner, A. Damm, and G. Kuhlmann
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Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Nitrogen oxides (NOx = NO + NO2) are air pollutants which are co-emitted with CO2 during high-temperature combustion processes. Monitoring NOx emissions is crucial for assessing air quality and for providing proxy estimates of CO2 emissions. Satellite observations, such as those from the TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinel-5P satellite, provide global coverage at high temporal resolution. However, satellites measure only NO2, necessitating a conversion to NOx. Previous studies have applied a constant NO2-to-NOx conversion factor. In this paper, we develop a more realistic model for NO2-to-NOx conversion and apply it to TROPOMI data of 2020 and 2021. To achieve this, we analysed plume-resolving simulations from the MicroHH large-eddy simulation model with chemistry for the Bełchatów (PL), Jänschwalde (DE), Matimba (ZA) and Medupi (ZA) power plants, as well as a metallurgical plant in Lipetsk (RU). We used the cross-sectional flux method to calculate NO, NO2 and NOx line densities from simulated NO and NO2 columns and derived NO2-to-NOx conversion factors as a function of the time since emission. Since the method of converting NO2 to NOx presented in this paper assumes steady-state conditions and that the conversion factors can be modelled by a negative exponential function, we validated the conversion factors using the same MicroHH data. Finally, we applied the derived conversion factors to TROPOMI NO2 observations of the same sources. The validation of the NO2-to-NOx conversion factors shows that they can account for the NOx chemistry in plumes, in particular for the conversion between NO and NO2 near the source and for the chemical loss of NOx further downstream. When applying these time-since-emission-dependent conversion factors, biases in NOx emissions estimated from TROPOMI NO2 images are greatly reduced from between −50 % and −42 % to between only −9.5 % and −0.5 % in comparison with reported emissions. Single-overpass estimates can be quantified with an uncertainty of 20 %–27 %, while annual NOx emission estimates have uncertainties in the range of 4 %–21 % but are highly dependent on the number of successful retrievals. Although more simulations covering a wider range of meteorological and trace gas background conditions will be needed to generalise the approach, this study marks an important step towards a consistent, uniform, high-resolution and near-real-time estimation of NOx emissions – especially with regard to upcoming NO2-monitoring satellites such as Sentinel-4, Sentinel-5 and CO2M.
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- 2024
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9. Sexual abuse and harsh punishment in early life are associated with more obsessive-compulsive symptoms in adulthood: An online survey
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M. Król, Y. Cao, and E.J. Kirkham
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IntroductionChildhood and adolescent maltreatment (CAM) is associated with many psychiatric conditions, including obsessive-compulsive disorder (OCD). However, it remains unclear whether the severity of OCD symptoms vary according to the type of stress encountered in early life.MethodA sample of 345 participants (174 of whom had OCD) completed online measures of CAM (Child Abuse and Trauma Scale; CATS), OCD (Obsessive-Compulsive Inventory-Revised; OCI-R), anxiety, and depression (Hospital Anxiety and Depression Scale; HADS).Regression analysis was used to examine associations between OCD symptoms and four subtypes of CAM: emotional abuse, neglect/home environment, punishment, and sexual abuse. Anxiety and depression were included as control variables.ResultsHigher levels of sexual abuse and punishment were significantly associated with more OCD symptoms irrespective of scores on measures of anxiety and depression. Emotional abuse and neglect/home environment were not significantly associated with OCD symptoms.DiscussionThese findings highlight the prospect of a specific role for harsh punishment and sexual abuse in the development of OCD. Future studies should examine this possibility using longitudinal designs. Health professionals should be mindful that individuals with OCD may have experienced heightened levels of CAM, especially in the domains of punishment and sexual abuse.
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- 2022
10. Online survey of treatment experiences for obsessive-compulsive disorder
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E.J. Kirkham, Y. Cao, and M. Król
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IntroductionThere is a lack of knowledge about the treatment experiences of people living with obsessive-compulsive disorder (OCD).MethodParticipants with OCD (n= 202) took part in an online survey in which they answered questions about what treatment they had received. They also completed measures of current OCD, anxiety and depression.ResultsScores above the clinical cut-off for OCD were high (> 70%) across the sample, irrespective of what kind of treatment had been received. Despite this, most participants felt their OCD was better now than it had been pre-treatment. Mean OCD scores were similar between treatment groups (OCD-focused, partly OCD-focused, non-OCD focused, no treatment), though there was some evidence that OCD-focused treatment was associated with lower OCD scores, especially for symptoms of hoarding, neutralising and ordering.DiscussionThese findings contribute to evidence of unmet need in OCD care. Practitioners should be aware that OCD is often a chronic condition which requires specialist care, and may require more than one course of treatment.
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- 2022
11. Spectroscopic studies of heavy metal cations influence on the structure of synthetic hydrated calcium aluminosilicates
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M. Król, P. Florek, K. Dziża, and W. Mozgawa
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Instrumentation ,Spectroscopy ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry - Published
- 2023
12. Neural Networks Based on Ultrafast Time-Delayed Effects in Exciton Polaritons
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R. Mirek, A. Opala, M. Furman, M. Król, K. Tyszka, B. Seredyński, W. Pacuski, J. Suffczyński, J. Szczytko, M. Matuszewski, and B. Piętka
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Computer Science::Emerging Technologies ,Condensed Matter - Mesoscale and Nanoscale Physics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,FOS: Physical sciences ,General Physics and Astronomy ,Physics - Optics ,Optics (physics.optics) - Abstract
We demonstrate that time-delayed nonlinear effects in exciton-polaritons can be used to construct neural networks where information is coded in optical pulses arriving consecutively on the sample. The highly nonlinear effects are induced by time-dependent interactions with the excitonic reservoir. These nonlinearities allow to create a nonlinear XOR logic gate that can perform operations on the picosecond timescale. An optoelectronic neural network based on the constructed logic gate performs classification of spoken digits with a high accuracy rate.
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- 2022
13. Neuromorphic Binarized Polariton Networks
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Dario Ballarini, Timothy Chi Hin Liew, Andrzej Opala, Magdalena Furman, Paolo Comaron, Krzysztof Tyszka, Jan Suffczyński, Barbara Piętka, Rafał Mirek, Wojciech Pacuski, M. Król, Michał Matuszewski, Bartłomiej Seredyński, Jacek Szczytko, and Daniele Sanvitto
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Letter ,Computer science ,Computation ,Bioengineering ,02 engineering and technology ,Exciton-polaritons ,Artificial Intelligence ,Biological neural network ,Electronic engineering ,Humans ,General Materials Science ,binary network ,Neurons ,Artificial neural network ,Mechanical Engineering ,nonlinear optics ,Brain ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,microcavities ,exciton-polaritons ,Semiconductors ,Coupling (computer programming) ,Neuromorphic engineering ,Pattern recognition (psychology) ,Neural Networks, Computer ,0210 nano-technology ,Efficient energy use - Abstract
The rapid development of artificial neural networks and applied artificial intelligence has led to many applications. However, current software implementation of neural networks is severely limited in terms of performance and energy efficiency. It is believed that further progress requires the development of neuromorphic systems, in which hardware directly mimics the neuronal network structure of a human brain. Here, we propose theoretically and realize experimentally an optical network of nodes performing binary operations. The nonlinearity required for efficient computation is provided by semiconductor microcavities in the strong quantum light-matter coupling regime, which exhibit exciton–polariton interactions. We demonstrate the system performance against a pattern recognition task, obtaining accuracy on a par with state-of-the-art hardware implementations. Our work opens the way to ultrafast and energy-efficient neuromorphic systems taking advantage of ultrastrong optical nonlinearity of polaritons.
- Published
- 2021
14. A study of bearing capacity of skirted octagonal footings resting on different sands
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M. Król, Tomasz Tański, L. A. Dobrzański, and R. Maniara
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Materials science ,Metallurgy ,Alloy ,Nucleation ,02 engineering and technology ,Solidus ,Liquidus ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,engineering ,General Materials Science ,Composite material ,Magnesium alloy ,Ingot ,0210 nano-technology ,Thermal analysis ,Eutectic system - Abstract
Purpose: After a thorough study of literature it is concluded that the studies related to unskirted/skirted octagonal footings on sand have not yet been investigated. Thus, this paper presents a numerical analysis to assess the ultimate bearing capacity of the unskirted, unskirted-embedded, singly and doubly skirted octagonal footings resting on different sands (S1, S2, and S3). The length of skirt and depth of the embedded footing were varied from 0.0B to 1.5B. Design/methodology/approach: The numerical square and octagonal footing with singly and doubly skirted footing models were developed using Plaxis 3D software. Findings: The results of the doubly skirted octagonal footings ultimate bearing capacity were marginally higher in comparison to the singly skirted footing at all normalised skirt depths as well as for all sands up to a Ds/B ratio 0.25 beyond which the increase in the ultimate bearing capacity in case of doubly skirted footing was appreciable. Research limitations/implications: The results presented in this paper were based on numerical analysis. However, for the actual footings the soil placement and compaction, details of skirt construction and the stress level will be different from the numerical analysis. Further investigations using full-scale numerical models simulating field size footings were recommended to generalize the results. Originality/value: No such study on singly and doubly skirted octagonal shaped footings were conducted so far. Hence, an attempt was made in this article to predict the bearing capacity of those footings using Plaxis 3D.
- Published
- 2021
15. Synthesis and Characterization of Novel Aluminum Composites: A Compo-Casting Approach with ZrO2 , Al2O3 , and SiC
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S. Farahany, M.K. Hamdani, M.R. Salehloo, M. Krol, and E. Cheraghali
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hybrid composite ,aluminum ,compo-casting ,wear ,bismuth ,Technology (General) ,T1-995 - Abstract
The present study evaluates the microstructural features, mechanical properties, and wear characteristics of the newly developed hybrid composite of A356/ZrO2/Al2O3/SiC produced by compo-casting at 605±5 °C, 600 rpm for 15 minutes with less than 30% solid fraction in which Bi and Sn were added separately to the matrix before introducing reinforcements. FESEM micrographs and corresponding EDS illustrated the successful incorporation of particles in the matrix. Fine particles of ZrO2 were observed close to the coarse Al2O3, and SiC particles, along with Bi and Sn elements, were detected at the eutectic evolution region. The A356+Bi/Al2O3+ZrO2+SiC hybrid composite exhibited the lowest specific wear rate (1.642 ×10-7cm3/Nm) and friction coefficient (0.31) under applied loads of 5, 10, and 20 N, in line with the highest hardness (73.4 HBN). Analysis of the worn surfaces revealed that the wear mechanism is mostly adhesive in all synthesized composites, which changed to the combination of adhesive and abrasive mode in the case containing Bi and SiC. Inserting Bi not only leads to the refinement of eutectic Si but also enhances the adhesion between the matrix/particles and improves lubricity. This, in turn, reduces the wear rate and coefficient of friction, ultimately improving the performance of the hybrid composite.
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- 2024
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16. Spin polarization of exciton-polariton condensate in a photonic synthetic effective magnetic field
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R. Mirek, M. Furman, M. Król, B. Seredyński, K. Łempicka-Mirek, K. Tyszka, W. Pacuski, M. Matuszewski, J. Szczytko, and B. Piętka
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Condensed Matter - Mesoscale and Nanoscale Physics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,FOS: Physical sciences - Abstract
We investigate the spin polarization of localized exciton-polariton condensates. We demonstrate the presence of an effective magnetic field leading to the formation of elliptically polarized condensates. We show that this synthetic field has an entirely photonic origin, which we believe is unique for the CdTe-based microcavities. Moreover, the degree of spin polarization of localized polariton condensates in samples with magnetic ions depends on the excitation power or polarization of the non-resonant excitation laser. In an external magnetic field, the semimagnetic condensate spontaneously builds up strong spin polarization. Based on the magnetic field behavior of the condensate in the presence of magnetic ions, we apply a model that allows us to estimate the polariton-polariton interaction strength in a CdTe-system to approx. 0.8 $\mu \text{eV}\!\cdot\!\mu \text{m}^2$.
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- 2022
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17. Realizing Optical Persistent Spin Helix and Stern-Gerlach Deflection in an Anisotropic Liquid Crystal Microcavity
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Barbara Piętka, Katarzyna Rechcińska, Przemysław Oliwa, Pavlos G. Lagoudakis, Rafał Mazur, Helgi Sigurdsson, Przemysław Morawiak, Michał Matuszewski, Przemysław Kula, Wiktor Piecek, Jacek Szczytko, Witold Bardyszewski, and M. Król
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Condensed Matter::Quantum Gases ,Physics ,Stern–Gerlach experiment ,Photon ,Condensed matter physics ,Spintronics ,Condensed Matter::Other ,Physics::Optics ,General Physics and Astronomy ,02 engineering and technology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,01 natural sciences ,Symmetry (physics) ,Momentum ,symbols.namesake ,Liquid crystal ,0103 physical sciences ,symbols ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology ,Spin (physics) ,Hamiltonian (quantum mechanics) - Abstract
Spin-orbit interactions which couple the spin of a particle with its momentum degrees of freedom lie at the center of spintronic applications. Of special interest in semiconductor physics are Rashba and Dresselhaus spin-orbit coupling. When equal in strength, the Rashba and Dresselhaus fields result in SU(2) spin rotation symmetry and emergence of the persistent spin helix only investigated for charge carriers in semiconductor quantum wells. Recently, a synthetic Rashba-Dresselhaus Hamiltonian was shown to describe cavity photons confined in a microcavity filled with optically anisotropic liquid crystal. In this Letter, we present a purely optical realization of two types of spin patterns corresponding to the persistent spin helix and the Stern-Gerlach experiment in such a cavity. We show how the symmetry of the Hamiltonian results in spatial oscillations of the spin orientation of photons traveling in the plane of the cavity.
- Published
- 2021
18. OS10.4.A A macrophage-based drug delivery platform for glioma treatment
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M Sun, M Bialasek, T Rygiel, M Król, M Weller, and T Weiss
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
Background There is an urgent need for more effective treatment strategies against gliomas. At present, even though various drugs have potent anti-tumor activity in vitro, their application in vivo is limited by ineffective delivery and systemic toxicity. Therefore, novel strategies are needed to deliver these drugs effectively and safely to the tumor site. Here, we developed an adoptive transfer strategy against malignant brain tumors utilizing macrophages that are loaded with ferritin-protein cages containing drugs or other proteins and transfer these nanocarriers to cancer cells in vitro and in vivo. Material and Methods Live-time imaging, microscopy and flow cytometry were utilized to investigate the transfer of ferritin cages from loaded macrophages to human or mouse glioma cells. Co-cultures of glioma cells and macrophages loaded with ferritin-drug cages were used to study the anti-glioma activity in vitro and orthotopic immunocompetent mouse glioma models were used to study the anti-glioma activity in vivo. Affinity purification-mass spectrometry (AP-MS) was used to elucidate the mechanisms of transfer by characterizing the interactome of ferritin cages within macrophages and cancer cells. Results We observed a high transfer efficiency of ferritin-cages from loaded macrophages into human and mouse glioma cells in vitro in co-culture assays and confirmed the transfer from macrophages to glioma cells also in vivo upon intravenous or intratumoral treatment of GL-261 or CT-2A glioma-bearing mice. To study the anti-glioma activity with therapeutically active payloads, we loaded murine/human macrophages with ferritin cages carrying cytotoxic payloads. Co-culture of these loaded macrophages with murine or human glioma cells in vitro revealed a time- and concentration-dependent cytotoxicity to glioma cells. In vivo, intravenous or intratumoral administration of ferritin-drug protein cages was tolerated without toxicities and conferred a survival benefit in two orthotopic murine glioma models (GL-261 and CT-2A). Interactome studies of ferritin-cage-binding proteins revealed phagocytic and cytoskeleton re-arrangement pathways to be involved in uptake and transfer of ferritin-cages from macrophages to glioma cells. Conclusion This ‘Trojan Horse’ approach constitutes a promising platform to deliver cytotoxic drugs effectively and safely to gliomas and provides a rationale for clinical translation.
- Published
- 2022
19. Proton-Coupled Electron Transfer Dynamics in the Obligate Mycobacterial Supercomplex III2IV2
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Daniel Riepl, Ana P. Gamiz-Hernandez, Terezia Kovalova, Sylwia M. Król, Sophie L. Mader, Dan Sjöstrand, Pia Ädelroth, Martin Högbom, Peter Brzezinski, and Ville R.I. Kaila
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Biophysics ,Cell Biology ,Biochemistry - Published
- 2022
20. Full spectroscopic characterization of clinker minerals (anhydrous cement)
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M. Król, A. Koleżyński, P. Florek, P. Jeleń, D. Kozień, and W. Mozgawa
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Inorganic Chemistry ,Organic Chemistry ,Spectroscopy ,Analytical Chemistry - Published
- 2022
21. Tunable optical spin Hall effect in a liquid crystal microcavity
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Wiktor Piecek, Jacek Szczytko, M. Król, Daniel Stephan, Rafał Mazur, K. Lekenta, Przemysław Morawiak, Barbara Piętka, Rafał Mirek, Karolina Łempicka, Przemysław Kula, and Pavlos G. Lagoudakis
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Physics ,lcsh:Applied optics. Photonics ,Letter ,Photon ,Spintronics ,Condensed matter physics ,Dephasing ,lcsh:TA1501-1820 ,02 engineering and technology ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Paramagnetism ,0103 physical sciences ,Spin Hall effect ,lcsh:QC350-467 ,010306 general physics ,0210 nano-technology ,lcsh:Optics. Light ,Spin-½ - Abstract
The spin Hall effect, a key enabler in the field of spintronics, underlies the capability to control spin currents over macroscopic distances. The effect was initially predicted by D'Yakonov and Perel1 and has been recently brought to the foreground by its realization in paramagnetic metals by Hirsch2 and in semiconductors3 by Sih et al. Whereas the rapid dephasing of electrons poses severe limitations to the manipulation of macroscopic spin currents, the concept of replacing fermionic charges with neutral bosons such as photons in stratified media has brought some tangible advances in terms of comparatively lossless propagation and ease of detection4–7. These advances have led to several manifestations of the spin Hall effect with light, ranging from semiconductor microcavities8,9 to metasurfaces10. To date the observations have been limited to built-in effective magnetic fields that underpin the formation of spatial spin currents. Here we demonstrate external control of spin currents by modulating the splitting between transverse electric and magnetic fields in liquid crystals integrated in microcavities.
- Published
- 2018
22. Energy-efficient neural network inference with microcavity exciton polaritons
- Author
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Andrzej Opala, Dario Ballarini, M. Król, Krzysztof Tyszka, Michał Matuszewski, Jacek Szczytko, Daniele Sanvitto, Barbara Piętka, Rafał Mirek, Timothy Chi Hin Liew, M. Furman, and School of Physical and Mathematical Sciences
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FOS: Computer and information sciences ,Photon ,Artificial neural network ,Computer science ,General Physics and Astronomy ,Computer Science - Emerging Technologies ,Physics::Optics ,FOS: Physical sciences ,Exciton-polaritons ,Topology ,Classification ,Nonlinear system ,Interferometry ,Emerging Technologies (cs.ET) ,Orders of magnitude (time) ,Physics [Science] ,Polariton ,Artificial-Intelligence ,Efficient energy use ,Physics - Optics ,Optics (physics.optics) - Abstract
We propose all-optical neural networks characterized by very high energy efficiency and performance density of inference. We argue that the use of microcavity exciton-polaritons allows to take advantage of the properties of both photons and electrons in a seamless manner. This results in strong optical nonlinearity without the use of optoelectronic conversion. We propose a design of a realistic neural network and estimate energy cost to be at the level of attojoules per bit, also when including the optoelectronic conversion at the input and output of the network, several orders of magnitude below state-of-the-art hardware implementations. We propose two kinds of nonlinear binarized nodes based either on optical phase shifts and interferometry or on polariton spin rotations. Ministry of Education (MOE) Published version M.M. acknowledges support from National Science Center, Poland Grant No. 2017/25/Z/ST3/03032 under the QuantERA program. A.O. acknowledges support from National Science Center, Poland Grant No. 2016/22/E/ ST3/00045. R.M. acknowledges support from National Science Center, Poland Grant No. 2019/33/N/ST3/02019. B.P. acknowldges support from National Science Center, Poland Grant No. 2020/37/B/ST3/01657. K.T. acknowldges support from National Science Center, Poland Grant No. 2020/04/X/ST7/01379. T.L. acknowledges the support of the Singapore Ministry of Education, via the Academic research fund project MOE2019-T2-1-004. D.B. and D.S. acknowledge support from the project FISR2020- COVID, WaveSense (FISR2020IP_04324), and the PRIN 2017 InPhoPOL.
- Published
- 2021
23. SAN: an Integrated Unmanned Air Vehicles Interdictor System Concept
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R. Woźniak, J. Błaszczyk, M. Król, W. Koperski, and P. M. Błaszczyk
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air defence ,Engineering ,business.industry ,lcsh:Electronics ,lcsh:TK7800-8360 ,lcsh:TP155-156 ,General Medicine ,drone ,unmanned air vehicle systems ,Work (electrical) ,Systems engineering ,System concept ,anti-terrorist security ,lcsh:Chemical engineering ,business - Abstract
The development of unmanned air vehicles (UAVs) has been very rapid recently. The wide accessibility of UAVs has unlocked a great potential for the malicious or accidental damage or destruction of property or other aircraft in flight. UAVs can be used for espionage, contraband, and the trafficking or transport of arms and hazardous materials. Every month sees a growing number of reports of incidents that involve remote-controlled UAVs operated for aerial video recording. These incidents justify undertaking research into minimizing the hazards which UAVs may potentially cause. A concept was developed for a solution dedicated to this problem and comprising an integrated modular anti-UAV system for application in commercial (civilian) markets in the areas of security of mass events, strategic enterprises, and critical strategic infrastructure in Poland. The proposed system is intended to incapacitate any UAVs that breach a predefined air space and bring the incapacitated UAVs safely to the ground. The project is developed jointly by the Institute of Armament Technology at the Military University of Technology (Warsaw, Poland) and Polish company Ellipsis Sp. z o.o.
- Published
- 2017
24. Sources and sinks of carbonyl sulfide inferred from tower and mobile atmospheric observations in the Netherlands
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A. Zanchetta, L. M. J. Kooijmans, S. van Heuven, A. Scifo, H. A. Scheeren, I. Mammarella, U. Karstens, J. Ma, M. Krol, and H. Chen
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Ecology ,QH540-549.5 ,Life ,QH501-531 ,Geology ,QE1-996.5 - Abstract
Carbonyl sulfide (COS) is a promising tracer for the estimation of terrestrial ecosystem gross primary production (GPP). However, understanding its non-GPP-related sources and sinks, e.g., anthropogenic sources and soil sources and sinks, is also critical to the success of the approach. Here we infer the regional sources and sinks of COS using continuous in situ mole fraction profile measurements of COS along the 60 m tall Lutjewad tower (1 m a.s.l.; 53∘24′ N, 6∘21′ E) in the Netherlands. To identify potential sources that caused the observed enhancements of COS mole fractions at Lutjewad, both discrete flask samples and in situ measurements in the province of Groningen were made from a mobile van using a quantum cascade laser spectrometer (QCLS). We also simulated the COS mole fractions at Lutjewad using the Stochastic Time-Inverted Lagrangian Transport (STILT) model combined with emission inventories and plant uptake fluxes. We determined the nighttime COS fluxes to be -3.0±2.6 pmol m−2 s−1 using the radon-tracer correlation approach and Lutjewad observations. Furthermore, we identified and quantified several COS sources, including biodigesters, sugar production facilities and silicon carbide production facilities in the province of Groningen. Moreover, the simulation results show that the observed COS enhancements can be partially explained by known industrial sources of COS and CS2, in particular from the Ruhr Valley (51.5∘ N, 7.2∘ E) and Antwerp (51.2∘ N, 4.4∘ E) areas. The contribution of likely missing anthropogenic sources of COS and CS2 in the inventory may be significant. The impact of the identified sources in the province of Groningen is estimated to be negligible in terms of the observed COS enhancements. However, in specific conditions, these sources may influence the measurements in Lutjewad. These results are valuable for improving our understanding of the sources and sinks of COS, contributing to the use of COS as a tracer for GPP.
- Published
- 2023
- Full Text
- View/download PDF
25. Difference schemes for systems of second order nonlinear ODEs on a semi-infinite interval
- Author
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Myroslav V. Kutniv, M. Król, and O.I. Pazdriy
- Subjects
Numerical Analysis ,Semi-infinite ,Applied Mathematics ,010102 general mathematics ,Mathematical analysis ,010103 numerical & computational mathematics ,Interval (mathematics) ,01 natural sciences ,Nonlinear differential equations ,Computational Mathematics ,Operator (computer programming) ,Order (group theory) ,Uniqueness ,Boundary value problem ,0101 mathematics ,Mathematics ,Nonlinear ode - Abstract
The three-point difference schemes of high order accuracy for the numerical solving boundary value problems on a semi-infinite interval for systems of second order nonlinear ordinary differential equations with a not self-conjugate operator are constructed and justified. We proved the existence and uniqueness of solutions of the three-point difference schemes and obtained the estimate of their accuracy. The results of numerical experiments which confirm the theoretical results are given.
- Published
- 2017
26. Realization of Exact Three-Point Difference Schemes for Nonlinear Boundary-Value Problems on the Semiaxis
- Author
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M. V. Kutniv and M. Król
- Subjects
General Mathematics ,010103 numerical & computational mathematics ,01 natural sciences ,Nonlinear differential equations ,010101 applied mathematics ,Rate of convergence ,Applied mathematics ,Point (geometry) ,Nonlinear boundary value problem ,Uniqueness ,0101 mathematics ,Algebra over a field ,High order ,Realization (systems) ,Mathematics - Abstract
New algorithmic realization of exact three-point difference schemes via the three-point difference schemes of high order of accuracy is proposed for the numerical solution of boundary-value problems for systems of nonlinear ordinary differential equations on the semiaxis. We study the existence and uniqueness of the solution of three-point difference schemes and estimate the rate of convergence. The results of numerical experiments are also presented.
- Published
- 2017
27. Exciton-polaritons in multilayer WSe$_2$ in a planar microcavity
- Author
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Magdalena Grzeszczyk, Takashi Taniguchi, Kenji Watanabe, Barbara Piętka, Rafał Mirek, Maciej R. Molas, Jacek Szczytko, Sara Piotrowska, Marek Potemski, M. Król, Karol Nogajewski, Karolina Łempicka, Katarzyna Rechcińska, Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G ), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées
- Subjects
Materials science ,Photon ,Exciton ,Binding energy ,FOS: Physical sciences ,Physics::Optics ,02 engineering and technology ,Dielectric ,Exciton-polaritons ,Polaron ,01 natural sciences ,7. Clean energy ,Quasi particles ,Condensed Matter::Materials Science ,Planar ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,General Materials Science ,010306 general physics ,ComputingMilieux_MISCELLANEOUS ,[PHYS]Physics [physics] ,Condensed Matter - Mesoscale and Nanoscale Physics ,business.industry ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,3. Good health ,Mechanics of Materials ,Optoelectronics ,0210 nano-technology ,business - Abstract
Due to high binding energy and oscillator strength, excitons in thin flakes of transition metal dichalcogenides constitute a perfect foundation for realizing a strongly coupled light-matter system. In this paper we investigate mono- and few-layer WSe$_2$ flakes encapsulated in hexagonal boron nitride and incorporated into a planar dielectric cavity. We use an open cavity design which provides tunability of the cavity mode energy by as much as 150 meV. We observe a strong coupling regime between the cavity photons and the neutral excitons in direct-bandgap monolayer WSe$_2$, as well as in few-layer WSe$_2$ flakes exhibiting indirect bandgap. We discuss the dependence of the exciton's oscillator strength and resonance linewidth on the number of layers and predict the exciton-photon coupling strength.
- Published
- 2019
28. Engineering spin-orbit synthetic Hamiltonians in liquid-crystal optical cavities
- Author
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Wiktor Piecek, Jacek Szczytko, Barbara Piętka, Pavlos G. Lagoudakis, Rafał Mirek, Witold Bardyszewski, Przemysław Kula, Michał Matuszewski, Karolina Łempicka, M. Król, Przemysław Morawiak, Rafał Mazur, and Katarzyna Rechcińska
- Subjects
Physics ,Multidisciplinary ,Photon ,business.industry ,Parity (physics) ,Electromagnetic radiation ,law.invention ,law ,Liquid crystal ,Optical cavity ,Quantum mechanics ,Photonics ,business ,Quantum - Abstract
Inducing optical spin-orbit coupling The coupling of the spin-orbit interactions in solid-state systems can give rise to a wide range of exotic electronic transport effects. But solid-state systems tend to be somewhat limited in their flexibility because the spin-orbit coupling is fixed. By contrast, optical systems have recently been shown to mimic complex solid-state systems, with flexibility in design providing the ability to control and manipulate the system properties. Using a liquid crystal–filled photonic cavity, Rechcińska et al. emulated an artificial Rashba-Dresselhaus spin-orbit coupling in a photonic system and showed control of an artificial Zeeman splitting. The results illustrate a powerful approach of engineering synthetic Hamiltonians with photons for the simulation of nontrivial condensed matter and quantum phenomena. Science , this issue p. 727
- Published
- 2019
29. Exciton-Polaritons in a Tunable Microcavity with 2D-Perovskite
- Author
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Maria Kaminska, Wiktor Piecek, Jacek Szczytko, Rafał Mazur, A. Wincukiewicz, Barbara Piętka, M. Furman, Katarzyna Rechcińska, Karolina Łempicka, M. Muszyński, and M. Król
- Subjects
Condensed Matter::Quantum Gases ,Coupling ,Photon ,Materials science ,Photoluminescence ,Condensed Matter::Other ,business.industry ,Exciton ,Physics::Optics ,Exciton-polaritons ,Condensed Matter::Materials Science ,Planar ,Optoelectronics ,Condensed Matter::Strongly Correlated Electrons ,Spontaneous emission ,business ,Perovskite (structure) - Abstract
We realized a tunable planar microcavity containing a 2D-layered perovskite (C6H5(CH2)2NH3)2PbI4. A strong light-matter coupling regime between the perovskite exciton and the confined photon mode is evidenced at room temperature in angular-resolved reflectivity and photoluminescence experiments.
- Published
- 2019
30. Observation of second-order meron polarization textures in optical microcavities
- Author
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Przemysław Kula, Krzysztof Tyszka, Przemysław Morawiak, Pavlos G. Lagoudakis, Katarzyna Rechcińska, Rafał Mazur, M. Król, Wiktor Piecek, Jacek Szczytko, Andrzej Opala, Helgi Sigurdsson, Michał Matuszewski, Barbara Piętka, Przemysław Oliwa, and Witold Bardyszewski
- Subjects
Electromagnetic field ,Physics ,Photon ,Meron ,Field (physics) ,Physics::Optics ,02 engineering and technology ,Quantum Hall effect ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Quantum mechanics ,0103 physical sciences ,Gauge theory ,Quantum field theory ,010306 general physics ,0210 nano-technology ,Circular polarization - Abstract
Multicomponent Bose–Einstein condensates, quantum Hall systems, and chiral magnetic materials display twists and knots in the continuous symmetries of their order parameters known as skyrmions. Originally discovered as solutions to the nonlinear sigma model in quantum field theory, these vectorial excitations are quantified by a topological winding number dictating their interactions and global properties of the host system. Here, we report the experimental observation of a stable individual second-order meron and antimeron appearing in an electromagnetic field. We realize these complex textures by confining light into a liquid-crystal-filled cavity that, through its anisotropic refractive index, provides an adjustable artificial photonic gauge field that couples the cavity photon motion to its polarization, resulting in the formation of these fundamental vectorial vortex states of light. Our observations could help bring topologically robust room-temperature optical vector textures into the field of photonic information processing and storage.
- Published
- 2021
31. Relative Reflection Difference as a Method for Measuring the Thickness of the Exfoliated MoSe2 Layers
- Author
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Jacek Szczytko, K. Lekenta, M. Król, M. Grzeszczyk, Karolina Łempicka, Adam Babiński, Barbara Piętka, and K. Norowski
- Subjects
Materials science ,Optics ,business.industry ,Reflection (physics) ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,business ,01 natural sciences ,0104 chemical sciences - Published
- 2017
32. (Cd,Zn,Mg)Te-based microcavity on MgTe sacrificial buffer: Growth, lift-off, and transmission studies of polaritons
- Author
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Kamil Sobczak, Wojciech Pacuski, M. Król, Bartłomiej Seredyński, Maciej Ściesiek, P. Starzyk, Jacek Szczytko, Daniel Stephan, Jolanta Borysiuk, J.-G. Rousset, Barbara Piętka, and Rafał Mirek
- Subjects
Materials science ,Photoluminescence ,Physics and Astronomy (miscellaneous) ,Opacity ,Physics::Optics ,02 engineering and technology ,01 natural sciences ,Spectral line ,Condensed Matter::Materials Science ,symbols.namesake ,0103 physical sciences ,Polariton ,General Materials Science ,010306 general physics ,Quantum well ,Condensed Matter::Quantum Gases ,Zeeman effect ,Condensed Matter::Other ,business.industry ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Semiconductor ,symbols ,Optoelectronics ,0210 nano-technology ,business ,Molecular beam epitaxy - Abstract
Opaque substrates precluded, so far, transmission studies of II-VI semiconductor microcavities. This work presents the design and molecular beam epitaxy growth of semimagnetic (Cd,Zn,Mn)Te quantum wells embedded into a (Cd,Zn,Mg)Te-based microcavity, which can be easily separated from the GaAs substrate. Our lift-off process relies on the use of a MgTe sacrificial layer which stratifies in contact with water. This allowed us to achieve a II-VI microcavity prepared for transmission measurements. We evidence the strong light-matter coupling regime using photoluminescence, reflectivity, and transmission measurements at the same spot on the sample. By comparing a series of reflectance spectra before and after lift-off, we prove that the microcavity quality remains high. Thanks to Mn content in quantum wells we show the giant Zeeman splitting of semimagnetic exciton-polaritons in our transmitting structure.
- Published
- 2018
33. Spin polarized semimagnetic exciton-polariton condensate in magnetic field
- Author
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J.-G. Rousset, Jacek Szczytko, Daniel Stephan, Michał Matuszewski, Michał Nawrocki, Wojciech Pacuski, K. Lekenta, M. Król, Barbara Piętka, and Rafał Mirek
- Subjects
Exciton ,Population ,FOS: Physical sciences ,lcsh:Medicine ,Physics::Optics ,02 engineering and technology ,01 natural sciences ,Article ,symbols.namesake ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Polariton ,010306 general physics ,education ,lcsh:Science ,Spin-½ ,Physics ,Condensed Matter::Quantum Gases ,education.field_of_study ,Multidisciplinary ,Zeeman effect ,Condensed matter physics ,Spin polarization ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter::Other ,lcsh:R ,021001 nanoscience & nanotechnology ,Magnetic field ,symbols ,lcsh:Q ,0210 nano-technology ,Excitation - Abstract
Owing to their integer spin, exciton-polaritons in microcavities can be used for observation of non-equilibrium Bose-Einstein condensation in solid state. However, spin-related phenomena of such condensates are difficult to explore due to the relatively small Zeeman effect of standard semiconductor microcavity systems and the strong tendency to sustain an equal population of two spin components, which precludes the observation of condensates with a well defined spin projection along the axis of the system. The enhancement of the Zeeman splitting can be achieved by introducing magnetic ions to the quantum wells, and consequently forming semimagnetic polaritons. In this system, increasing magnetic field can induce polariton condensation at constant excitation power. Here we evidence the spin polarization of a semimagnetic polaritons condensate exhibiting a circularly polarized emission over 95% even in a moderate magnetic field of about 3 T. Furthermore, we show that unlike nonmagnetic polaritons, an increase on excitation power results in an increase of the semimagnetic polaritons condensate spin polarization. These properties open new possibilities for testing theoretically predicted phenomena of spin polarized condensate., 9 pages, 5 figures
- Published
- 2018
34. Giant spin Meissner effect in a non-equilibrium exciton-polariton gas
- Author
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Michał Matuszewski, J.-G. Rousset, Alexey Kavokin, Jacek Szczytko, K. Lekenta, Barbara Piętka, Rafał Mirek, Daniel Stephan, Wojciech Pacuski, and M. Król
- Subjects
Superconductivity ,Physics ,Condensed Matter::Quantum Gases ,Condensed matter physics ,Condensed Matter::Other ,Exciton ,Non-equilibrium thermodynamics ,FOS: Physical sciences ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Meissner effect ,Quantum Gases (cond-mat.quant-gas) ,Phase (matter) ,0103 physical sciences ,Polariton ,Zeeman energy ,Condensed Matter - Quantum Gases ,010306 general physics ,0210 nano-technology ,Spin-½ - Abstract
The suppression of Zeeman energy splitting due to spin-dependent interactions within a Bose-Einstein condensate (the spin Meissner effect) was predicted to occur up to a certain value of magnetic field strength. We report a clear observation of this effect in semimagnetic microcavities which exhibit the giant Zeeman energy splitting between two spin-polarised polariton states as high as 2 meV, and demonstrate that partial suppression of energy difference occurs already in the uncondensed phase in a striking similarity to the up-critical superconductors in the fluctuation dominated regime. These observations are explained quantitatively by a kinetic model accounting for both the condensed and uncondensed polaritons and taking into account the non-equilibrium character of the system., Comment: 12 pages, 10 figures
- Published
- 2018
- Full Text
- View/download PDF
35. Influence of Clonal Plasma Cell Contamination of Peripheral Blood Stem Cell Autografts on Progression and Survival in Multiple Myeloma Patients After Autologous Peripheral Blood Stem Cell Transplantation in Long-term Observation
- Author
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A. Waszczuk-Gajda, M. Feliksbrot-Bratosiewicz, M. Król, E. Snarski, J. Drozd-Sokołowska, P. Biecek, Z. Lewandowski, J. Peradzyńska, W.W. Jędrzejczak, and J. Dwilewicz-Trojaczek
- Subjects
Oncology ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,Plasma Cells ,macromolecular substances ,CD38 ,Plasma cell ,Transplantation, Autologous ,CD19 ,Disease-Free Survival ,immune system diseases ,hemic and lymphatic diseases ,Internal medicine ,medicine ,Humans ,Autografts ,Multiple myeloma ,CD20 ,Transplantation ,Chemotherapy ,Peripheral Blood Stem Cell Transplantation ,biology ,business.industry ,technology, industry, and agriculture ,Middle Aged ,medicine.disease ,Flow Cytometry ,medicine.anatomical_structure ,biology.protein ,Disease Progression ,Peripheral Blood Stem Cells ,Surgery ,Female ,Stem cell ,Neoplasm Recurrence, Local ,business ,Multiple Myeloma - Abstract
Background High-dose chemotherapy followed by autologous peripheral blood stem cell transplantation (auto-PBSCT) remains the mainstay of treatment of eligible patients diagnosed multiple myeloma. The role of clonal plasma cell (CPC) contamination was found as a reason for relapse, but results in terms of survival, progression, and purging were ambiguous. Therefore, the aim of the study was to explore the influence of CPC contamination in the autograft on survival and progression after auto-PBSCT. Study Design The study included 59 patients diagnosed and treated for multiple myeloma in 1998–2004. Cells with coexpression of CD38+++CD138++CD56+ and lacking the expression of CD45, CD19, CD10, CD20, and CD23 were considered CPC in flow cytometry. Results The risk of death and progression after auto-PBSCT increased significantly by 10% (P Conclusions High clonal plasma cell contamination (>2.96 ×1 06/kg; 90th percentile of CPC number) is associated with the worst progression-free survival and overall survival. Therefore purging in vitro might be considered for the patients with the highest CPC contamination. Negative consequences of CPC contamination on the risk of death are observed for only 2 years after auto-PBSCT. Thereafter only those patients who had lower CPC contamination survived.
- Published
- 2017
36. Magnetic field effect on the lasing threshold of a semimagnetic polariton condensate
- Author
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K. Lekenta, Barbara Piętka, Rafał Mirek, Jacek Szczytko, J.-G. Rousset, Wojciech Pacuski, M. Król, and Michał Nawrocki
- Subjects
Condensed Matter::Quantum Gases ,Physics ,Zeeman effect ,Condensed matter physics ,Condensed Matter::Other ,Physics::Optics ,02 engineering and technology ,Magnetic field effect ,021001 nanoscience & nanotechnology ,01 natural sciences ,Magnetic field ,symbols.namesake ,0103 physical sciences ,symbols ,Polariton ,010306 general physics ,0210 nano-technology ,Lasing threshold ,Quantum well - Abstract
We evidence magnetic field triggered polariton lasing in a microcavity containing semimagnetic quantum wells. This effect is associated with a decrease of the polariton lasing threshold power in magnetic field. The observed magnetic field dependence of the threshold power systematically exhibits a minimum which only weakly depends on the zero-field photon-exciton detuning. These results are interpreted as a consequence of the polariton giant Zeeman splitting which in magnetic field leads to a decrease of the number of accessible states in the lowest polariton branch by a factor of 2, and substantially changes the photon-exciton detuning.
- Published
- 2017
37. 2s exciton-polariton revealed in an external magnetic field
- Author
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Piotr Stepnicki, Marek Potemski, Jacek Szczytko, K. Lekenta, Michał Matuszewski, Barbara Piętka, Rafał Mirek, François Morier-Genoud, M. Król, Maciej R. Molas, Nataliya Bobrovska, and Benoit Deveaud
- Subjects
Photon ,Exciton ,FOS: Physical sciences ,Physics::Optics ,02 engineering and technology ,01 natural sciences ,Condensed Matter::Materials Science ,0103 physical sciences ,Polariton ,010306 general physics ,Quantum well ,Physics ,Condensed Matter::Quantum Gases ,Condensed matter physics ,business.industry ,Condensed Matter::Other ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Magnetic field ,Semiconductor ,Quantum Gases (cond-mat.quant-gas) ,Excited state ,Strong coupling ,0210 nano-technology ,business ,Condensed Matter - Quantum Gases - Abstract
We demonstrate the existence of the excited state of an exciton-polariton in a semiconductor microcavity. The strong coupling of the quantum well heavy-hole exciton in an excited 2s state to the cavity photon is observed in non-zero magnetic field due to surprisingly fast increase of Rabi energy of the 2s exciton-polariton in magnetic field. This effect is explained by a strong modification of the wave-function of the relative electron-hole motion for the 2s exciton state., 5 pages, 5 figures
- Published
- 2017
38. Angular dependence of giant Zeeman effect for semimagnetic cavity polariton
- Author
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Michał Kulczykowski, Michał Nawrocki, Jacek Szczytko, J.-G. Rousset, Wojciech Pacuski, M. Król, K. Lekenta, Barbara Piętka, Rafał Mirek, and Michał Matuszewski
- Subjects
Photon ,FOS: Physical sciences ,Physics::Optics ,02 engineering and technology ,01 natural sciences ,symbols.namesake ,Condensed Matter::Materials Science ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Polariton ,Wave vector ,010306 general physics ,Quantum well ,Physics ,Condensed Matter::Quantum Gases ,Zeeman effect ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,business.industry ,Condensed Matter::Other ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Magnetic field ,Semiconductor ,symbols ,Zeeman energy ,0210 nano-technology ,business - Abstract
The observation of spin-related phenomena of microcavity polaritons has been limited due to the weak Zeeman effect of nonmagnetic semiconductors. We demonstrate that the incorporation of magnetic ions into quantum wells placed in a nonmagnetic microcavity results in enhanced effects of magnetic field on exciton-polaritons. We show that in such a structure the Zeeman splitting of exciton-polaritons strongly depends on the photon-exciton detuning and polariton wave vector. Our experimental data are explained by a model where the impact of magnetic field on the lower polariton state is directly inherited from the excitonic component, and the coupling strength to the cavity photon is modified by an external magnetic field.
- Published
- 2017
39. Doubly dressed bosons - exciton-polaritons in a strong terahertz field
- Author
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K. Lekenta, François Morier-Genoud, S. Winnerl, Jacek Szczytko, Alexej Pashkin, Daniel Stephan, Harald Schneider, Manfred Helm, M. Teich, Michał Matuszewski, M. Król, Nataliya Bobrovska, Barbara Piętka, Rafał Mirek, and Benoit Deveaud
- Subjects
Physics ,Condensed Matter::Quantum Gases ,Photon ,Condensed matter physics ,Field (physics) ,Terahertz radiation ,Exciton ,General Physics and Astronomy ,Physics::Optics ,FOS: Physical sciences ,02 engineering and technology ,Exciton-polaritons ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,3. Good health ,Quantum Gases (cond-mat.quant-gas) ,0103 physical sciences ,Quasiparticle ,010306 general physics ,0210 nano-technology ,Condensed Matter - Quantum Gases ,Quantum ,Boson - Abstract
We demonstrate the existence of a novel quasiparticle: an exciton in a semiconductor doubly dressed with two photons of different wavelengths: near infrared cavity photon and terahertz (THz) photon, with the THz coupling strength approaching the ultra-strong coupling regime. This quasiparticle is composed of three different bosons, being a mixture of a matter-light quasiparticle. Our observations are confirmed by a detailed theoretical analysis, treating quantum mechanically all three bosonic fields. The doubly dressed quasiparticles retain the bosonic nature of their constituents, but their internal quantum structure strongly depends on the intensity of the applied terahertz field., Comment: 12 pages, 9 figures
- Published
- 2017
- Full Text
- View/download PDF
40. Sixteen years of MOPITT satellite data strongly constrain Amazon CO fire emissions
- Author
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S. Naus, L. G. Domingues, M. Krol, I. T. Luijkx, L. V. Gatti, J. B. Miller, E. Gloor, S. Basu, C. Correia, G. Koren, H. M. Worden, J. Flemming, G. Pétron, and W. Peters
- Subjects
Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Despite the consensus on the overall downward trend in Amazon forest loss in the previous decade, estimates of yearly carbon emissions from deforestation still vary widely. Estimated carbon emissions are currently often based on data from local logging activity reports, changes in remotely sensed biomass, and remote detection of fire hotspots and burned area. Here, we use 16 years of satellite-derived carbon monoxide (CO) columns to constrain fire CO emissions from the Amazon Basin between 2003 and 2018. Through data assimilation, we produce 3 d average maps of fire CO emissions over the Amazon, which we verified to be consistent with a long-term monitoring programme of aircraft CO profiles over five sites in the Amazon. Our new product independently confirms a long-term decrease of 54 % in deforestation-related CO emissions over the study period. Interannual variability is large, with known anomalously dry years showing a more than 4-fold increase in basin-wide fire emissions relative to wet years. At the level of individual Brazilian states, we find that both soil moisture anomalies and human ignitions determine fire activity, suggesting that future carbon release from fires depends on drought intensity as much as on continued forest protection. Our study shows that the atmospheric composition perspective on deforestation is a valuable additional monitoring instrument that complements existing bottom-up and remote sensing methods for land-use change. Extension of such a perspective to an operational framework is timely considering the observed increased fire intensity in the Amazon Basin between 2019 and 2021.
- Published
- 2022
- Full Text
- View/download PDF
41. The role of genetic instability in stimulation of angiogenesis in liver metastases of sporadic colorectal cancer
- Author
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J. Sierdzinski, M. Król, M. Feliksbrot-Bratosiewicz, F. Macrae, W. Otto, U. Wilkowojska, and E. Wolińska
- Subjects
Hepatology ,business.industry ,Angiogenesis ,Gastroenterology ,Cancer research ,Medicine ,Stimulation ,business ,Sporadic colorectal cancer - Published
- 2019
42. Angiogenesis factors indicate for recurrence in HCC surgical patients
- Author
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Marek Krawczyk, W. Otto, J. Sierdzinski, U. Wilkowojska, E. Wilczek, and M. Król
- Subjects
Oncology ,medicine.medical_specialty ,Hepatology ,business.industry ,Angiogenesis ,Internal medicine ,Gastroenterology ,Medicine ,business ,Surgical patients - Published
- 2016
- Full Text
- View/download PDF
43. Exponential stability of Itô-type evolution differential equations of first and second order
- Author
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M. Król
- Subjects
Statistics and Probability ,Stochastic partial differential equation ,Examples of differential equations ,Applied Mathematics ,General Mathematics ,Stability theory ,Mathematical analysis ,C0-semigroup ,Exponential integrator ,Differential algebraic equation ,Mathematics ,Numerical stability ,Numerical partial differential equations - Abstract
The exponential stability of evolution differential equations obtained on the basis of heat conduction equations is studied. To determine the boundaries of stochastic stability of the solution of these equations, we use the method of construction of a Lyapunov functional.
- Published
- 2011
44. Expression of endothelial progenitor cells and vascular endothelial growth factor according to genomic instability in colorectal liver metastases
- Author
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J. Sierdzinski, E. Wolińska, W. Otto, M. Król, and F. Macrae
- Subjects
Genome instability ,Vascular endothelial growth factor ,chemistry.chemical_compound ,Hepatology ,chemistry ,business.industry ,Gastroenterology ,Cancer research ,Medicine ,Progenitor cell ,business - Published
- 2018
45. Evaluation of two common source estimation measurement strategies using large-eddy simulation of plume dispersion under neutral atmospheric conditions
- Author
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A. Ražnjević, C. van Heerwaarden, and M. Krol
- Subjects
Environmental engineering ,TA170-171 ,Earthwork. Foundations ,TA715-787 - Abstract
This study uses large-eddy simulations (LESs) to evaluate two widely used observational techniques that estimate point source emissions. We evaluate the use of car measurements perpendicular to the wind direction and the commonly used Other Test Method 33A (OTM 33A). The LES study simulates a plume from a point source released into a stationary, homogeneous, and neutral atmospheric surface layer over flat terrain. This choice is motivated by our ambition to validate the observational methods under controlled conditions where they are expected to perform well since the sources of uncertainties are minimized. Three plumes with different release heights were sampled in a manner that mimics sampling according to car transects and the stationary OTM 33A. Subsequently, source strength estimates are compared to the true source strength used in the simulation. Standard deviations of the estimated source strengths decay proportionally to the inverse of the square root of the number of averaged transects, showing statistical independence of individual samples. The analysis shows that for the car transect measurements at least 15 repeated measurement series need to be averaged to obtain a source strength within 40 % of the true source strength. For the OTM 33A analysis, which recommends measurements within 200 m of the source, the estimates of source strengths have similar values close to the source, which is caused by insufficient dispersion of the plume by turbulent mixing close to the source. Additionally, the derived source strength is substantially overestimated with OTM 33A. This overestimation is driven by the proposed OTM 33A dispersion coefficients, which are too large for this specific case. This suggests that the conditions under which the OTM 33A dispersion constants were derived were likely influenced by motions with length scales beyond the scale of the surface layer. Lastly, our simulations indicate that, due to wind-shear effects, the position of the time-averaged centerline of the plumes may differ from the plume emission height. This mismatch can be an additional source of error if a Gaussian plume model (GPM) is used to interpret the measurement. In the case of the car transect measurements, a correct source estimate then requires an adjustment of the source height in the GPM.
- Published
- 2022
- Full Text
- View/download PDF
46. Influence of cooling rate on crystallization, structure and mechanical properties of MCMgAl6Zn1 alloy
- Author
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L.A. Dobrzański, M. Król, and T. Tański
- Subjects
lcsh:TA401-492 ,lcsh:Materials of engineering and construction. Mechanics of materials ,structure ,mechanical properties ,magnesium alloy ,thermal analysis - Abstract
This work presents an influence of cooling rate on crystallization process, structure and mechanical properties of MCMgAl6Zn1 castmagnesium alloy. The experiments were performed using the novel Universal Metallurgical Simulator and Analyzer Platform. Theapparatus enabled recording the temperature during refrigerate magnesium alloy with three different cooling rates, i.e. 0.6, 1.2 and2.4°C/s and calculate a first derivative. Based on first derivative results, nucleation temperature, beginning of nucleation of eutecticand solidus temperature were described. It was fund that the formation temperatures of various thermal parameters, mechanicalproperties (hardness and ultimate compressive strength) and grain size are shifting with an increasing cooling rate.
- Published
- 2010
47. Technical note: Interpretation of field observations of point-source methane plume using observation-driven large-eddy simulations
- Author
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A. Ražnjević, C. van Heerwaarden, B. van Stratum, A. Hensen, I. Velzeboer, P. van den Bulk, and M. Krol
- Subjects
Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This study demonstrates the ability of large-eddy simulation (LES) forced by a large-scale model to reproduce plume dispersion in an actual field campaign. Our aim is to bring together field observations taken under non-ideal conditions and LES to show that this combination can help to derive point-source strengths from sparse observations. We analyze results from a single-day case study based on data collected near an oil well during the ROMEO campaign (ROmanian Methane Emissions from Oil and gas) that took place in October 2019. We set up our LES using boundary conditions derived from the meteorological reanalysis ERA5 and released a point source in line with the configuration in the field. The weather conditions produced by the LES show close agreement with field observations, although the observed wind field showed complex features due to the absence of synoptic forcing. In order to align the plume direction with field observations, we created a second simulation experiment with manipulated wind fields that better resemble the observations. Using these LESs, the estimated source strengths agree well with the emitted artificial tracer gas plume, indicating the suitability of LES to infer source strengths from observations under complex conditions. To further harvest the added value of LES, higher-order statistical moments of the simulated plume were analyzed. Here, we found good agreement with plumes from previous LES and laboratory experiments in channel flows. We derived a length scale of plume mixing from the boundary layer height, the mean wind speed and convective velocity scale. It was demonstrated that this length scale represents the distance from the source at which the predominant plume behavior transfers from meandering dispersion to relative dispersion.
- Published
- 2022
- Full Text
- View/download PDF
48. Thermal and mechanical characteristics of cast Mg-Al-Zn alloy
- Author
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L. A. Dobrzański and M. Król
- Subjects
UMSA ,lcsh:TA401-492 ,lcsh:Materials of engineering and construction. Mechanics of materials ,Magnesium alloy ,thermal analysis - Abstract
This work presents effect of cooling rate on the grain size, mechanical properties and thermal characteristic results of MCMgAl9Zn1 cast alloy. The solidification process was studied using the cooling curve and crystallization curve at solidification rate ranging from 0.6°C/s up to 2.4°C/s. It was determined that the higher solidification rate increases the magnesium dendrite nucleation temperature. In addition, it was observed that the non-equilibrium solidus temperature and the grain size constituent decreases when the solidification rate increases.
- Published
- 2010
49. Durability of cement and geopolimer composites
- Author
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T Błaszczyński and M Król
- Subjects
Cement ,Materials science ,business.industry ,0211 other engineering and technologies ,02 engineering and technology ,engineering.material ,Durability ,Geopolymer ,Iron ore ,Fly ash ,021105 building & construction ,Smelting ,engineering ,Coal ,021108 energy ,Composite material ,business ,Chemical composition - Abstract
Concrete structures are constantly moving in the direction of improving the durability. This main feature depends on many factors, which are the composition of concrete mix, the usage of additives and admixtures and the place, where material will work and carry the load. The introduction of new geopolymer binders for geopolymer structures adds a new aspect that is type of used activator. This substance with strongly alkaline reaction is divided because of the physical state, the alkaline degree and above all the chemical composition. Taking into account, that at present the geopolymer binders are made essentially from waste materials or by products from the combustion of coal or iron ore smelting, unambiguous determination of the effect of the activator on the properties of the geopolymer material requires a number of trials, researches and observation. This paper shows the influence of the most alkaline activators on the basic parameters of the durability of geopolymer binders. In this study there were used a highly alkaline hydroxides, water glasses and granules, which are waste materials in a variety of processes taking place in a chemical plants. As the substrate of geopolymer binders there were used fly ash which came from coal and high calcium ash from the burning of lignite.
- Published
- 2017
50. Magnetic field tuning of exciton-polaritons in a semiconductor microcavity
- Author
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Barbara Piętka, Igor Tralle, François Morier-Genoud, Piotr Stepnicki, Benoit Deveaud, Jacek Szczytko, Maciej R. Molas, Jerzy Łusakowski, M. Król, Michał Matuszewski, Marek Potemski, A. A. L. Nicolet, D. Zygmunt, and Paweł Zięba
- Subjects
Photon ,Oscillator strength ,Exciton ,FOS: Physical sciences ,Physics::Optics ,02 engineering and technology ,Exciton-polaritons ,01 natural sciences ,Condensed Matter::Materials Science ,symbols.namesake ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Polariton ,010306 general physics ,Biexciton ,Condensed Matter::Quantum Gases ,Physics ,Zeeman effect ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed matter physics ,Condensed Matter::Other ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Magnetic field ,symbols ,0210 nano-technology - Abstract
We detail the influence of a magnetic field on exciton-polaritons inside a semiconductor microcavity. Magnetic field can be used as a tuning parameter for exciton and photon resonances. We discuss the change of the exciton energy, the oscillator strength, and redistribution of the polariton density along the dispersion curves due to the magnetically induced detuning. We have observed that field-induced shrinkage of the exciton wave function has a direct influence not only on the exciton oscillator strength, which is observed to increase with the magnetic field, but also on the polariton linewidth. We discuss the effect of the Zeeman splitting on polaritons the magnitude of which changes with the exciton Hopfield coefficient and can be modeled by independent coupling of the two spin components of excitons with cavity photons.
- Published
- 2015
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