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109 results on '"Gerhardt, I."'

1. Single organic molecules for photonic quantum technologies

Author

Toninelli, C., Gerhardt, I., Clark, A. S., Reserbat-Plantey, A., Götzinger, S., Ristanovic, Z., Colautti, M., Lombardi, P., Major, K. D., Deperasińska, I., Pernice, W. H., Koppens, F. H. L., Kozankiewicz, B., Gourdon, A., Sandoghdar, V., and Orrit, M.

Subjects
Quantum Physics
Abstract

Isolating single molecules in the solid state has allowed fundamental experiments in basic and applied sciences. When cooled down to liquid helium temperature, certain molecules show transition lines, that are tens of megahertz wide, limited only by the excited state lifetime. The extreme flexibility in the synthesis of organic materials provides, at low costs, a wide palette of emission wavelengths and supporting matrices for such single chromophores. In the last decades, the controlled coupling to photonic structures has led to an optimized interaction efficiency with light. Molecules can hence be operated as single photon sources and as non-linear elements with competitive performance in terms of coherence, scalability and compatibility with diverse integrated platforms. Moreover, they can be used as transducers for the optical read-out of fields and material properties, with the promise of single-quanta resolution in the sensing of charges and motion. We show that quantum emitters based on single molecules hold promise to play a key role in the development of quantum science and technologies., Comment: 24 pages, 6 figures, 1 table

Published
2020
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3. Integrated Diamond Optics for Single Photon Detection

Author

Siyushev, P., Kaiser, F., Jacques, V., Gerhardt, I., Bischof, S., Fedder, H., Dodson, J., Markham, M., Twitchen, D., Jelezko, F., and Wrachtrup, J.

Subjects
Quantum Physics, Physics - Optics
Abstract

Optical detection of single defect centers in the solid state is a key element of novel quantum technologies. This includes the generation of single photons and quantum information processing. Unfortunately the brightness of such atomic emitters is limited. Therefore we experimentally demonstrate a novel and simple approach that uses off-the-shelf optical elements. The key component is a solid immersion lens made of diamond, the host material for single color centers. We improve the excitation and detection of single emitters by one order of magnitude, as predicted by theory., Comment: 10 pages, 3 figures

Published
2010
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4. Scanning Near-Field Optical Coherent Spectroscopy of Single Molecules at 1.4 Kelvin

Author

Gerhardt, I., Wrigge, G., Agio, M., Bushev, P., Zumofen, G., and Sandoghdar, V.

Subjects
Physics - Optics
Abstract

We present scanning near-field extinction spectra of single molecules embedded in a solid matrix. By varying the molecule-tip separation, we modify the line shape of the spectra, demonstrating the coherent nature of the interaction between the incident laser light and the excited state of the molecule. We compare the measured data with the outcome of numerical calculations and find a very good agreement., Comment: 3 pages, 5 figures, submitted to Optics Letters

Published
2007
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5. Strong extinction of a laser beam by a single molecule

Author

Gerhardt, I., Wrigge, G., Bushev, P., Zumofen, G., Pfab, R., and Sandoghdar, V.

Subjects
Quantum Physics
Abstract

We present an experiment where a single molecule strongly affects the amplitude and phase of a laser field emerging from a subwavelength aperture. We achieve a visibility of -6% in direct and +10% in cross-polarized detection schemes. Our analysis shows that a close to full extinction should be possible using near-field excitation., Comment: 5 pages, 4 figures, submitted to PRL

Published
2006
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9. Acute Cerebrovascular Disease in the Young: The Stroke in Young Fabry Patients Study

Author

Rolfs, Arndt, Fazekas, Franz, Grittner, Ulrike, Dichgans, Martin, Martus, Peter, Holzhausen, Martin, Böttcher, Tobias, Heuschmann, Peter U., Tatlisumak, Turgut, Tanislav, Christian, Jungehulsing, Gerhard J., Giese, Anne-Katrin, Putaala, Jukaa, Huber, Roman, Bodechtel, Ulf, Lichy, Christoph, Enzinger, Christian, Schmidt, Reinhold, Hennerici, Michael G., Kaps, Manfred, Kessler, Christof, Lackner, Karl, Paschke, Eduard, Meyer, Wolfgang, Mascher, Hermann, Riess, Olaf, Kolodny, Edwin, Norrving, Bo, Rolfs, A, Ginsberg, M, Hennerici, MG, Kessler, C, Kolodny, E, Martus, P, Norrving, B, Ringelstein, EB, Rothwell, PM, Venables, G, Bornstein, N, deDeyn, P, Dichgans, M, Fazekas, F, Markus, H, Rie, O, Biedermann, C, Böttcher, T, Brüderlein, K, Burmeister, J, Federow, I, König, F, Makowei, G, Niemann, D, Rolfs, A, Rösner, S, Zielke, S, Grittner, U, Martus, P, Holzhausen, M, Fazekas, F, Enzinger, C, Schmidt, R, Ropele, S, Windisch, M, Sterner, E, Bodamer, O, Fellgiebel, A, Hillen, U, Jonas, L, Kampmann, C, Kropp, P, Lackner, K, Laue, M, Mascher, H, Meyer, W, Paschke, E, Weidemann, F, Berrouschot, J, Stoll, A, Rokicha, A, Sternitzky, C, Thomä, M, DeDeyn, PP, Sheorajpanday, R, De Brabander, I, Yperzeele, L, Brouns, R, Oschmann, P, Pott, M, Schultes, K, Schultze, C, Hirsekorn, J, Jungehulsing, GJ, Villringer, A, Schmidt, W, Liman, T, Nowe, T, Ebinger, M, Wille, A, Loui, H, Objartel, A, übelacker, A, Mette, R, Jegzentis, K, Nabavi, DG, Crome, O, Bahr, D, Ebke, M, Platte, B, Kleinen, C, Mermolja Gunther, K, Heide, W, Pape, O, Hanssen, JR, Stangenberg, D, Klingelhofer, J, Schmidt, B, Schwarz, S, Schwarze, J, Frandlih, L, Iwanow, J, Steinbach, I, Krieger, D, Boysen, G, Leth Jeppesen, L, Petersen, A, Reichmann, H, Becker, U, Dzialkowski, I, Hentschel, H, Lautenschlager, C, Hanso, H, Gahn, G, Ziemssen, T, Fleischer, K, Sehr, B, McCabe, DJH, Tobin, O, Kinsella, J, Murphy, RP, Jander, S, Hartung, HP, Siebler, M, Bottcher, C, Kohne, A, Platzen, J, Brosig, TC, Rothhammer, V, Henseler, C, Neumann-Haefelin, T, Singer, OC, Ermis, U, dos Santos, IMRM, Schuhmann, C, van de Loo, S, Kaps, M, Allendorfer, J, Tanislav, C, Brandtner, M, Muir, K, Dani, K, MacDougall, N, Smith, W, Rowe, A, Welch, A, Fazekas, F, Schrotter, G, Krenn, U, Horner, S, Pendl, B, Pluta-Fuerst, A, Trummer, U, Kessler, C, Chatzopoulos, M, v Sarnowski, Bettina, Schminke, Ulf, Link, T, Khaw, A, Nieber, E, Zierz, S, Muller, T, Wegener, N, Wartenberg, K, Gaul, C, Richter, D, Rosenkranz, M, Krützelmann, AC, Hoppe, J, Choe, CU, Narr, S, Magnus, TU, Thomalla, G, Leypoldt, F, Otto, D, Lichy, C, Hacke, W, Barrows, RJ, Tatlisumak, T, Putaala, J, Curtze, S, Metso, M, Willeit, J, Furtner, M, Spiegel, M, Knoflach, MH, Prantl, B, Witte, OW, Brämer, D, Günther, A, Prell, T, Herzau, C, Aurich, K, Deuschl, G, Wodarg, F, Zimmermann, P, Eschenfelder, CC, Levsen, M, Weber, JR, Marecek, SM, Schneider, D, Michalski, D, Kloppig, W, Küppers-Tiedt, L, Schneider, M, Schulz, A, Matzen, P, Weise, C, Hobohm, C, Meier, H, Langos, R, Urban, D, Gerhardt, I, Thijs, V, Lemmens, R, Marcelis, E, Hulsbosch, C, Aichner, F, Haring, HP, Bach, E, Machado Candido, J, e Silva, AA, Lourenco, M, de Sousa, AIM, Derex, L, Cho, TH, Díez-Tejedor, E, Fuentes, B, Martínez-Sanchez, P, Pérez-Guevara, MI, Hamer, H, Metz, A, Hallenberger, K, Müller, P, Baron, P, Bersano, A, Gattinoni, M, Vella, N, Mallia, M, Jauss, M, Adam, L, Heidler, F, Gube, C, Kiszka, M, Dichgans, M, Karpinska, A, Mewald, Y, Straub, V, Dörr, A, Zollver, A, Ringelstein, EB, Schilling, M, Borchert, A, Preuth, N, Duning, T, Kuhlenbäumer, G, Schulte, D, Rothwell, PM, Marquardt, L, Schlachetzki, F, Boy, S, Mädl, J, Ertl, GM, Fehm, NPR, Stadler, C, Benecke, R, Dudesek, A, Kolbaske, S, Lardurner, G, Sulzer, C, Zerbs, A, Lilek, S, Walleczek, AM, Sinadinowska, D, Janelidze, M, Beridze, M, Lobjanidze, N, Dzagnidze, A, Melms, A, Horber, K, Fink, I, Liske, B, Ludolph, AC, Huber, R, Knauer, K, Hendrich, C, Raubold, S, Czlonkowska, A, Baranowska, A, Blazejewska-Hyzorek, B, Lang, W, Kristoferitsch, W, Ferrari, J, Ulrich, E, Flamm-Horak, A, Lischka-Lindner, A, Schreiber, W, Demarin, V, Tranjec, Z, Bosner-Puretic, M, Jurašić, MJ, Basic Kes, V, Budisic, M, and Kopacevic, L

Published
2013
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12. Intraspecific variability of popcorn S7 lines for phosphorus efficiency in the soil

Author

GERHARDT, I. F. S., AMARAL JÚNIOR, A. T., GUIMARAES, L. J. M., SCHWANTES, I. A., SANTOS, A., KAMPHORST, S. H., LIMA, V. J., POBLETE, F. M., MYERS, G. O., Universidade Estadual do Norte Fluminense Darcy Ribeiro, LAURO JOSE MOREIRA GUIMARAES, CNPMS, Universidad de Talca, Chile, and Louisiana State University.

Subjects
Agricultura sustentável, Milho pipoca, Divergência genética, Fósforo, Zea mays, Estresse abiótico, Variação genética
Abstract

The expansion of agriculture, coupled with the need for sustainable cropping, is one of the greatest challenges of the scientific community working on the generation of new cultivars adapted to abiotic stress conditions. The aim of this study was to evaluate the variability of popcorn lines as to responsiveness and efficiency in phosphorus use, as a first step towards the implementation of a breeding program interested in the practice of sustainable agriculture. Twenty-five popcorn lines were evaluated in two locations with different phosphorus levels in the soil, using a randomized block design. The following traits were measured: plant height, ear height, female flowering date, male flowering date, male-female flowering interval, ear diameter, ear length, 100-grain weight, grain yield, popping expansion, and expanded popcorn volume per hectare. A combined analysis of variance and test of means were performed, and the lines were classified as to their phosphorus use efficiency, according to their production performance in the different environments. The genetic diversity between the lines was estimated by Tocher?s and UPGMA clustering methods, using generalized Mahalanobis distance. Lines L59, P7, P2, P3, P4, P8, P10, P9, L66, L70, L69, and P5 were efficient and responsive, whereas lines L75, L80, L61, L77, L63, L65, P1, L54, L53, L88, and L71 were inefficient and nonresponsive. Genetic variability was greater in the environments with low phosphorus in the soil, suggesting that the selection pressure exerted in the stressing environment is a decisive factor to obtain a higher expression of variability. Made available in DSpace on 2017-11-16T23:28:44Z (GMT). No. of bitstreams: 1 Intraspecificvariability.pdf: 615251 bytes, checksum: bcd3887c8cd3ea9aed0a31941e8b1f82 (MD5) Previous issue date: 2017-11-16

Published
2017

19. Promoters used in genetic transformation of plants

Author

GRUNENNVALDT, R. L., DEGENHARDT-GOLDBACH, J., GERHARDT, I. R., QUOIRIN, M., RENATA LUCIA GRUNENNVALDT, UFPR, JULIANA DEGENHARDT GOLDBACH, CNPF, ISABEL RODRIGUES GERHARDT, CNPTIA, and MARGUERITE QUOIRIN, UFPR.

Subjects
Tissues, Specific promoters, Promoter regions, Inducible promoters, Biotecnologia, Biotechnology
Abstract

The promoter is a DNA sequence that regulates the expression of a particular gene. Knowledge of the promoters used in gene constructs for genetic transformation is essential for successfully applying GM technology. Promoters can be classified as constitutive, inducible and organ/tissue specific. The use of inducible and organ/tissue promoters has gained importance, because of its extensive applicability. This review presents a summary of the different types of promoters with examples of some of them that have been identified and characterized for genetic transformation of various plant species.

Published
2015

21. Modelling and simulating non-stationary arrival processes to facilitate analysis

Author

Nelson, Barry L., Gerhardt, I., Nelson, Barry L., and Gerhardt, I.

Abstract

This paper introduces a method to model and simulate non-stationary, non-renewal arrival processes that depends only on the analyst setting intuitive and easily controllable parameters. Thus, it is suitable for assessing the impact of non-stationary, non-exponential, and non-independent arrivals on simulated performance when they are suspected. A specific implementation of the method is also described and provided for download.

Published
2011

25. Monolithic diamond optics for single photon detection

Author

Siyushev, P., primary, Kaiser, F., additional, Jacques, V., additional, Gerhardt, I., additional, Bischof, S., additional, Fedder, H., additional, Dodson, J., additional, Markham, M., additional, Twitchen, D., additional, Jelezko, F., additional, and Wrachtrup, J., additional

Published
2010
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34. Control and imaging of single-molecule spectral dynamics using a nano-electrode.

Author

Gerhardt, I., Wrigge, G., and Sandoghdar, V.

Subjects
*MOLECULES, *SPECTRUM analysis, *FLUORESCENCE, *TERPHENYL, *LUMINESCENCE, *ELECTRODES
Abstract

We study the influence of a scanning nano-electrode on the fluorescence excitation spectra of single terrylene molecules embedded in thin p-terphenyl films at cryogenic temperatures. We show that applied voltages of less than 10 V can result in reversible Stark shifts of up to 100 times and a linewidth increase greater than 10 times the natural linewidth. We discuss the potential of our experimental scheme for the direct imaging of individual two-level systems in the nanometer vicinity of single molecules. [ABSTRACT FROM AUTHOR]

Published
2009
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35. Efficient coupling of photons to a single molecule and the observation of its resonance fluorescence.

Author

Wrigge, G., Gerhardt, I., Hwang, J., Zumofen, G., and Sandoghdar, V.

Subjects
*DYES & dyeing, *MOLECULES, *PARTICLES (Nuclear physics), *COUPLING constants, *QUANTUM optics
Abstract

Single dye molecules at cryogenic temperatures exhibit many spectroscopic phenomena known from the study of free atoms and are thus promising candidates for experiments in fundamental quantum optics. However, the existing techniques for their detection have either sacrificed information on the coherence of the excited state or have been inefficient. Here, we show that these problems can be addressed by focusing the excitation light near to the extinction cross-section of a molecule. Our detection scheme enables us to explore resonance fluorescence over nine orders of magnitude of excitation intensity and to separate its coherent and incoherent parts. In the strong excitation regime, we demonstrate the first direct observation of the Mollow fluorescence triplet from a single solid-state emitter. Under weak excitation, we report the detection of a single molecule with an incident power as faint as 600 aW, paving the way for studying nonlinear effects with only a few photons. [ABSTRACT FROM AUTHOR]

Published
2008
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47. Structural Attributes and Photodynamics of Visible Spectrum Quantum Emitters in Hexagonal Boron Nitride

Author

Felipe Fávaro de Oliveira, Sen Yang, Jörg Wrachtrup, Torsten Rendler, Patrick Herlinger, Federico Paolucci, Ilja Gerhardt, Wafa Rouabeh, Youngwook Kim, Amit Finkler, Jurgen H. Smet, Andrej Denisenko, Nathan Chejanovsky, Mohammad Rezai, Chejanovsky, N., Rezai, M., Paolucci, F., Kim, Y., Rendler, T., Rouabeh, W., Favaro De Oliveira, F., Herlinger, P., Denisenko, A., Yang, S., Gerhardt, I., Finkler, A., Smet, J. H., and Wrachtrup, J.

Subjects
van der Waals materials, Materials science, Band gap, FOS: Physical sciences, Bioengineering, 02 engineering and technology, 01 natural sciences, 7. Clean energy, Molecular electronic transition, Settore FIS/03 - Fisica della Materia, symbols.namesake, 0103 physical sciences, Monolayer, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), hexagonal boron-nitride, General Materials Science, 010306 general physics, Common emitter, Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Mechanical Engineering, General Chemistry, Single quantum emitter, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Isotropic etching, symbols, Optoelectronics, Physics::Accelerator Physics, van der Waals force, 0210 nano-technology, Raman spectroscopy, business, Quantum Physics (quant-ph), Visible spectrum
Abstract

Newly discovered van der Waals materials like MoS$_2$, WSe$_2$, hexagonal boron nitride (h-BN), and recently $\mathrm{C}_2\mathrm{N}$ have sparked intensive research to unveil the quantum behavior associated with their 2D structure. Of great interest are 2D materials that host single quantum emitters. h-BN, with a band gap of 5.95 eV, has been shown to host single quantum emitters which are stable at room temperature in the UV and visible spectral range. In this paper we investigate correlations between h-BN structural features and emitter location from bulk down to the monolayer at room temperature. We demonstrate that chemical etching and ion irradiation can generate emitters in h-BN. We analyze the emitters' spectral features and show that they are dominated by the interaction of their electronic transition with a single Raman active mode of h-BN. Photodynamics analysis reveals diverse rates between the electronic states of the emitter. The emitters show excellent photo stability even under ambient conditions and in monolayers. Comparing the excitation polarization between different emitters unveils a connection between defect orientation and the h-BN hexagonal structure. The sharp spectral features, color diversity, room-temperature stability, long-lived metastable states, ease of fabrication, proximity of the emitters to the environment, outstanding chemical stability, and biocompatibility of h-BN provide a completely new class of systems that can be used for sensing and quantum photonics applications., In Nano Letters, ACS, 2016. Title change. Revision according to peer-review report. SI can be downloaded from http://pubs.acs.org/doi/suppl/10.1021/acs.nanolett.6b03268/suppl_file/nl6b03268_si_001.pdf

Published
2016

48. Femtosecond tunable light source with variable repetition rate between 640 kHz and 41 MHz with a 130 dB temporal pulse contrast ratio.

Author

Floess M, Steinle T, Gerhardt I, and Giessen H

Abstract

We demonstrate a femtosecond tunable light source with a variable pulse repetition rate based on a synchronously pumped fiber-feedback optical parametric oscillator (FFOPO) that incorporates an extended-cavity design. The repetition rate can be reduced by an acousto-optical modulator in the FFOPO pump beam. The extended FFOPO cavity supports signal oscillation down to the 64 th subharmonic. The high nonlinearity of the FFOPO threshold suppresses signal output for residual pump pulses that are transmitted by the pulse picker. We characterize the temporal pulse contrast ratio of the FFOPO signal output with a second-order cross-correlation measurement. This FFOPO system enables pulse picking with extraordinarily high values up to 111 dB suppression of adjacent pulses and exhibits a temporal contrast ratio that exceeds 130 dB. It generates fs-pulses with tunable wavelength from 1415-1750 nm and 2.5-3.8 µm and variable repetition rates ranging from 640 kHz to 41 MHz.

Published
2022
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49. Search for topological defect dark matter with a global network of optical magnetometers.

Author

Afach S, Buchler BC, Budker D, Dailey C, Derevianko A, Dumont V, Figueroa NL, Gerhardt I, Grujić ZD, Guo H, Hao C, Hamilton PS, Hedges M, Jackson Kimball DF, Kim D, Khamis S, Kornack T, Lebedev V, Lu ZT, Masia-Roig H, Monroy M, Padniuk M, Palm CA, Park SY, Paul KV, Penaflor A, Peng X, Pospelov M, Preston R, Pustelny S, Scholtes T, Segura PC, Semertzidis YK, Sheng D, Shin YC, Smiga JA, Stalnaker JE, Sulai I, Tandon D, Wang T, Weis A, Wickenbrock A, Wilson T, Wu T, Wurm D, Xiao W, Yang Y, Yu D, and Zhang J

Abstract

Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can form stable, macroscopic field configurations in the form of topological defects that could concentrate the dark matter density into many distinct, compact spatial regions that are small compared with the Galaxy but much larger than the Earth. Here we report the results of the search for transient signals from the domain walls of axion-like particles by using the global network of optical magnetometers for exotic (GNOME) physics searches. We search the data, consisting of correlated measurements from optical atomic magnetometers located in laboratories all over the world, for patterns of signals propagating through the network consistent with domain walls. The analysis of these data from a continuous month-long operation of GNOME finds no statistically significant signals, thus placing experimental constraints on such dark matter scenarios., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2021.)

Published
2021
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50. Single Photon Randomness based on a Defect Center in Diamond.

Author

Chen X, Greiner JN, Wrachtrup J, and Gerhardt I

Abstract

The prototype of a quantum random number generator is a single photon which impinges onto a beam splitter and is then detected by single photon detectors at one of the two output paths. Prior to detection, the photon is in a quantum mechanical superposition state of the two possible outcomes with -ideally- equal amplitudes until its position is determined by measurement. When the two output modes are observed by a single photon detector, the generated clicks can be interpreted as ones and zeros - and a raw random bit stream is obtained. Here we implement such a random bit generator based on single photons from a defect center in diamond. We investigate the single photon emission of the defect center by an anti-bunching measurement. This certifies the "quantumness" of the supplied photonic input state, while the random "decision" is still based on the vacuum fluctuations at the open port of the beam-splitter. Technical limitations, such as intensity fluctuations, mechanical drift, and bias are discussed. A number of ways to suppress such unwanted effects, and an a priori entropy estimation are presented. The single photon nature allows for a characterization of the non-classicality of the source, and allows to determine a background fraction. Due to the NV-center's superior stability and optical properties, we can operate the generator under ambient conditions around the clock. We present a true 24/7 operation of the implemented random bit generator.

Published
2019
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