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We experimentally demonstrate the storage of optical pulses (200ps-long, eight amplitude levels) on a photonic chip for over 70 pulse widths with minimum distortions in pulse shape and width using a Brillouin-based memory.

Physicochemical quality parameters, olfactory and gustatoryretronasal positive sensations of extra-virgin olive oils vary during storage leading to a decrease in the overall quality. Olive oil quality decline may prevent the compliance of olive oil quality with labeling and significantly reduce shelf life, resulting in important economic losses and negatively condition the consumer confidence. The feasibility of applying an electronic tongue to assess olive oils usual commercial light storage conditions and storage time was evaluated and compared with the discrimination potential of physicochemical or positive olfactory/gustatory sensorial parameters. Linear discriminant models, based on subsets of 58 electronic tongue sensor signals, selected by the meta-heuristic simulated annealing variable selection algorithm, allowed the correct classification of olive oils according to the light exposition conditions and/or storage time (sensitivities and specificities for leave-one-out cross-validation: 8296 %). The predictive performance of the E-tongue approach was further evaluated using an external independent dataset selected using the KennardStone algorithm and, in general, better classification rates (sensitivities and specificities for external dataset: 67100 %) were obtained compared to those achieved using physicochemical or sensorial data. So, the work carried out is a proof-of-principle that the proposed electrochemical device could be a practical and versatile tool for, in a single and fast electrochemical assay, successfully discriminate olive oils with different storage times and/or exposed to different light conditions., The authors acknowledge the financial support from the strategic funding of UID/BIO/04469/2013 unit, from Project POCI-01-0145-FEDER-006984—Associate Laboratory LSRELCM funded by FEDER funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI)—and by national funds through FCT—Fundação para a Ciência e a Tecnologia and under the strategic funding of UID/BIO/04469/2013 unit. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/104038/2014)., info:eu-repo/semantics/publishedVersion

We have studied light storage in an electromagnetically-induced-transparency medium. The total storage efficiency for the probe pulse has been presented, with and without adiabatic approximation. Storage with different control parameters has been discussed and the influences on storage efficiency have been addressed. We have found that good efficiency can be achieved by using easily controlled wave shapes for the control field.

We theoretically investigate a hybrid optomechanical system including two coupled optomechanical cavities in the presence of two strong pump fields and a weak probe field. The photon-hopping coupling of the cavities gives rise to two cavity supermodes whose resonant frequencies can be obtained in the probe transmission spectrum. In a strong photon-hopping coupling regime, there is a large coupling rate between the probe field and one of the two cavity supermodes that is called a bright mode. The optomechanical couplings between the bright mode and two mechanical resonators can cause double optomechanically induced transparency (OMIT), which can be employed to both separately and simultaneously store two weak probe pulses with different central frequencies. We obtain the group delay (light storage time) of the probe field in the hybrid optomechanical system. The results suggest that compared with that of a single cavity optomechanical system, the maximum value of the storage time roughly quadrupled in a particular case. The physical origin of the results is discussed. The hybrid optomechanical system opens an avenue of light storage in cavity optomechanics.

In this paper, we compare two methods to delay optical signals based on quasi-light storage (QLS). These methods are very simple and offer high-tunable storage times up to several thousand bits. Furthermore, they are transparent to the bit rate and modulation format of the signal. We explore the potentials and limitations of both methods. Fiber-based QLS is useful when high absolute delay is required and no loss or very small amount of attenuation can be tolerated. Frequency-to-time-conversion-based QLS can be used for the delay of very high bandwidth signals.

We perform a detailed theoretical analysis of electromagnetically induced absorption (EIA) and electromagnetically induced transparency (EIT) resonance width and amplitude as a function of laser power for different rates of spontaneous coherence transfer from the excited to the ground states. Our results show that the EIA signal undergoes a power broadening much smaller than EIT and is even free from power broadening in a specific condition that we analyse. Furthermore, the amplitude of the EIA signal is always larger than the amplitude of EIT, which constitutes an advantage in applications like magnetometers and light storage processes.

We demonstrate efficient storage and retrieval of light pulses by electromagnetically induced transparency (EIT) in a Pr^{3+}:Y_{2}SiO_{5} crystal. Using a ring-type multipass configuration, we increase the optical depth (OD) of the medium up to a factor of 16 towards OD≈96. Combining the large optical depth with optimized conditions for EIT, we reach a light storage efficiency of (76.3±3.5)%. In addition, we perform extended systematic measurements of the storage efficiency versus optical depth, control Rabi frequency, and probe pulse duration. The data confirm the theoretically expected behavior of an EIT-driven solid-state memory.

Stimulated Brillouin scattering (SBS) is a very fundamental interaction between light and travelling acoustic waves, which is mainly attributed to the electrostriction and photoelastic effects with the interaction strength being orders of magnitude larger than other nonlinearities. Although various photonic applications for all-optical light controlling based on SBS have been achieved in optical fiber and waveguides, the coherent light-acoustic interaction remains a challenge. Here, we experimentally demonstrated the Brillouin scattering induced transparency (BSIT) in a high quality optical microresonantor. Benefited from the triple-resonance in the whispering gallery cavity, the photon-phonon interaction is enhanced, and enables the light storage to the phonon, which has lifetime up to 10us. In addition, due to the phase matching condition, the stored circulating acoustic phonon can only interact with certain direction light, which leads to non-reciprocal light storage and retrieval. Our work paves the way towards the low power consumption integrated all-optical switching, isolator and circulator, as well as quantum memory., Comment: 5 pages, 3 figures

The large degrees of transparency that occurs in a medium where strong absorption would normally be expected is termed electromagnetically induced transparency. It is deliberately induced by one or more electromagnetic fields and relies on atomic states coherence and quantum interference. The necessary tools to understand the basic underlying physics will be presented, starting with a brief discussion of coherent population trapping, a closely related effect whose observation first raised interest in electromagnetically induced transparency phenomena.

Statistical properties of outgoing light pulses are studies after they have been stored in a medium of atoms in the tripod configuration. A generalized Hong-Ou-Mandel interference, storing of squeezed states and homodyne signal analysis are discussed in the context of their dependence on the parameters of the control fields used for light storage and release., Comment: 5 figures

We report measurements of the time-dependent phases of the leak and retrieved pulses obtained in electromagnetically-induced-transparency storage experiments with metastable helium vapor at room temperature. In particular, we investigate the influence of the optical detuning at two-photon resonance and provide numerical simulations of the full dynamical Maxwell-Bloch equations, which allow us to account for the experimental results.

In the framework of the temporal coupled mode theory we consider bound states embedded in the continuum (BSC) of photonic crystal waveguide as a capacity for light storage. A symmetry protected BSC occurs in two off-channel microresonators positioned symmetrically relative to the waveguide. We demonstrate that the symmetry protected BSC captures a fraction of a light pulse due to the Kerr effect as the pulse passes by the microresonators. However the amount of captured light is found to be strongly sensitive to the parameters of the gaussian light pulse such as basic frequency, duration and intensity. In contrast to the above case the BSC resulted from a full destructive interference of two eigenmodes of a single microresonator accumulates a fixed amount of light dependent on the material parameters of the microresonator but independent of the light pulse. The BSCs in the Fabry-Perot resonator show similar effects. We also show that the accumulated light can be released by a secondary pulse. These phenomena pave a way for all-optical storage and release of light.

Effects of ascorbic acid addition on the contents of retinyl palmitate isomers in skim milk treated with or without 3 mg/ mL added riboflavin were studied during storage for 30 h under fluorescent light. Light illumination induced the reduction of all-trans-retinyl palmitate and 13-cis isomer, but promoted the production of 9-cis isomer in the skim milk. Riboflavin increased the reduction of all-trans-retinyl palmitate, but decreased the formation of 9-cis isomer in light-stored skim milk. The addition of ascorbic acid greatly inhibited the light-induced reduction of all-trans-retinyl palmitate and 13-cis isomer in skim milks. Ascorbic acid also greatly increased the formation of 9-cis-retinyl palmitate in skim milks during light storage.

The effect of lead on photosynthetic light storage efficiency was measured by the photoacoustic method. The advantage of this method is in its directness, since the signal obtained by a hydrophone is proportional to that fraction of light energy that is dissipated as heat. This increases as less energy is stored photochemically if the photosynthetic apparatus is damaged. Cells of shape Synechococcus leopoliensis (Cyanobacteria) were grown in medium containing lead in concentrations of 0, 25, 50, 100, and 200 ppm. To avoid the co-precipitation of lead and phosphorus as lead phosphate, phosphorus was omitted from the media used during weeklong exposure to lead. Both chlorophyll concentration and photosynthetic energy storage efficiency decreased with time and with lead concentration. Reduction of photosynthesis progressed with time and increased with lead concentration, reaching up to 80% at the highest lead concentration after seven days.

Storage of light pulses in Rb vapour with bright Zeeman coherences and the associated enhanced absorption and steep negative dispersion is reported. Our experimental observations are qualitatively similar to the well-known proof-of-principle demonstration of light storage (D F Phillips et al 2001 Phys. Rev. Lett. 86 783), but obtained under conditions where electromagnetically induced transparency (EIT) does not exist and the slow-light dark-state polariton model does not apply. Under the present experimental conditions the retrieved pulses obtained in atomic media with dark or bright Zeeman coherences have very similar exponentially decaying slopes which are independent of the shape of the incoming signal pulse. Numerical modelling based on the optical Bloch equations reproduces the essential features of the experimental observations.

We have reported an experimental demonstration of Brillouin-scattering-induced transparency (BSIT) in a silica microsphere. Because of the phase-matching requirement, the non-reciprocal light storage based on the BSIT process is also observed in our experiment.

We report the experimental observation of coherent population oscillation (CPO-) based light storage in an atomic vapor cell at room temperature. Using the ultranarrow CPO between the ground levels of a $\ensuremath{\Lambda}$ system selected by polarization in metastable $^{4}\mathrm{He}$, such a light storage is experimentally shown to be phase preserving. As it does not involve any atomic coherences it has the advantage of being robust to dephasing effects such as small magnetic field inhomogeneities. The storage time is limited by the population lifetime of the ground states of the $\ensuremath{\Lambda}$ system.

In an optomechanical resonator, the optical and mechanical excitations can be coherent converted, which induces a transparency window for a weak probe laser beam. Here, we report an experimental study of transient optomechanical-induced transparency (OMIT) using the silica microcavity with breathing modes. We have also reported experimental studies on both OMIT and light storage under nearly the same conditions also illustrates the connections between these two closely related processes. As straightforward extension of the light storage process is to use a readout pulse that couples to a different optical mode. The resulting readout process enables optical wavelength or optical mode conversion.

Two formulations of 0.5% vancomycin hydrochloride (VM) eye drops (VM-B and VM-C eye drops) were prepared by dissolving commercial VM powder for injection with preserved water B (PWB) containing phosphate buffer and preserved water C (PWC) containing only antimicrobial preservative, respectively. The VM-B eye drops have neutral pH (about 6.3), and the VM-C eye drops acidic pH of about 3.5. The pharmaceutical examination of these eye drops was performed regarding its clinical application to MRSA eye infection. In an irritability test using a rabbit's eye, the average number of winks after instillation of one drop of VM-B eye drops was 0.8 times/min and significantly smaller than that of VM-C eye drops (2.0 times/min). In dark storage at 4 degrees C, no change of VM concentration in both eye drops was observed for 25 weeks after preparation and the mean residual concentrations as determined by the HPLC-UV (240 nm) method were constant over 90% for 8 weeks, of the initial concentration. However, the residual VM concentration of VM-B eye drops under a room condition declined to 58% after 4 weeks and 20% after 8 weeks, and VM in light storage at 40 degrees C was not detectable after 8 weeks. The drug concentration of VM-C eye drops declined to 83% after 4 weeks and 74% after 8 weeks under a room condition, and to 46% after 4 weeks and 20% after 8 weeks under light storage at 40 degrees C. Under these storage conditions, the precipitation of VM related crystals was observed in both the eye drops when the residual percentage of VM was lower than 80%. Judging from HPLC chromatograms of a solution of the precipitated crystals, it was suggested that this crystal was degradation products of VM. The VM-B eye drops was applied to a patient with MRSA eye infection, because other medication was not effective. After continuous instillation of a drop per times every hour to both eyes, MRSA in corneal culture turned out negative after one week, and the clinical condition was remarkably improved. On the basis of the result of eye-irritability, VM-B eye drops with neutral pH was suggested to be superior to acidic VM-C eye drops from a safety point of view. It was also indicated that VM-B eye drops can be effectively used for 8 weeks under dark storage at 4 degrees C for MRSA eye infection, which is a useful piece information for the proper usage of the VM eye drops.

We report the experimental observation of Coherent Population Oscillation (CPO) based light storage in thermal helium and cesium vapors.

Electromagnetically induced transparency (EIT) in metastable helium at room temperature is experimentally shown to exhibit light storage capabilities for intermediate values of the detuning between the coupling and probe beams and the center of the atomic Doppler profiles. An additional phase shift is shown to be imposed to the retrieved pulse of light when the EIT protocol is performed at non-zero optical detunings. The value of this phase shift is measured for different optical detunings between 0 and 2 GHz, and its origin is discussed., 6 pages, 5 figures

An on-farm storage trial was conducted at six sites in Nyandarua County using seed tubers of eight officially recognized Kenyan potato varieties and one commonly grown farmers’ variety called Cangi. The seeds were stored under diffuse light store (DLS) conditions in low-cost structures owned by the growers to test the feasibility of prolonged seed storage under on-farm conditions. Three farmers’ groups and three individual farmers were used in this study. In general, DLS wooden structures with iron sheet roof or mud-walled with iron sheet roofs were used for storage. Most of the varieties stored satisfactorily for up to 8 months. Kenya Mpya and Kenya Mavuno had higher overall acceptability than Sherekea, Asante, Desiree, Kenya Karibu, Tigoni and Dutch Robjin. Kenya Mpya, Sherekea and Kenya Mavuno had the least shrinkage following 8 months of storage. The unofficial cultivar Cangi which is the most popular in Nyandarua had poor storability but could be planted 2 to 3 months following harvest. Results indicated that DLS could be used by ware potato growers for prolonged seed storage the following season. This way the growers could be assured of good potato harvests due to the use of well sprouted tubers. This is critical in case of seasons with low or less than average rainfall as experienced in recent years.

Coherent inter-conversion between an optical and a mechanical excitation in an optomechanical resonator can be used for the storage of an optical pulse as an excitation in a mechanical oscillator. This optomechanical light storage is enabled by external writing and readout pulses at one mechanical frequency below the optical resonance. In this paper, we expand an earlier experimental study [Phys. Rev. Lett. 107, 133601 (2011)] on storing an optical pulse as a radial breathing mode in a silica microsphere. We show that the heterodyne beating between a readout pulse and the corresponding retrieved pulse features a periodic oscillation with a well-defined phase and with the beating period given by the mechanical frequency, demonstrating directly the coherent nature of the light storage process. The coherent inter-conversion accelerates with increasing optomechanical coupling rates, providing an effective mechanism for tailoring the temporal profile of the retrieved pulse. Experimental studies on both light storage and optomechanically induced transparency under nearly the same conditions also illustrate the connections between these two closely-related processes.

A low adoption of recommended seed potato (Solanum tuberosum L.) technologies in Ethiopia could be due to a lack of alternative seed potato production methods compatible with farmers' economic and agro-ecological conditions. A conjoint analysis (a technique used to measure relative contribution of product attributes) was conducted to elicit farmers' opinions on management attributes that they believed to affect yield and quality of potato. The study involved interviewing 324 farmers who grew seed potato in Jeldu and Welmera districts. The results showed that management attributes, such as storage method, hoeing combined with hill size, fertilizer rate (FR) and fungicide application (FA) frequency had larger effect on seed yield and quality than seed source, seed size, sprouting method, tillage frequency, and planting date. In both districts, using diffused light storage (DLS); hoeing twice, combined with big hills; and using recommended FR, combined with two FAs had significant positive effects on yield and quality of seed potato. In both districts, if all farmers switched to the best management attribute levels, potential increases in seed yield would be about two times the actual seed yield produced in 2010. The results suggest that it is possible to design better methods to produce seed potato compared with methods that farmers currently use. Extension personnel could use these results to recommend to farmers those management attributes that are the most important to improve yield and quality of seed potato in Ethiopia.

We propose a quantum memory for a single-photon wave packet in a superposition of two different colors, i.e., two different frequency components, using the electromagnetically induced transparency technique in a double-{\Lambda} system. We examine a specific configuration in which the two frequency components are able to exchange energy through a four-wave mixing process as they propagate, so the state of the incident photon is recovered periodically at certain positions in the medium. We investigate the propagation dynamics as a function of the relative phase between the coupling beams and the input single-photon frequency components. Moreover, by considering time-dependent coupling beams, we numerically simulate the storage and retrieval of a two-frequency-component single-photon qubit., Comment: 9 pages, 5 figures

The purified triacylglycerol fraction of rapeseed oil was used as a food lipid model to study the effects of β-carotene and γ-tocopherol on its oxidative stability in light. The triacylglycerol fraction of rapeseed oil was oxidized under fluorescent light at 25°C. Oxidation was followed by measuring peroxide value and the consumption of antioxidants. Under air, β-carotene (20 μg/g) was a pro-oxidant, whereas γ-tocopherol (20 μg/g) was an effective inhibitor of lipid oxidation. When both β-carotene (20 μg/g) and γ-tocopherol (20 to 50 μ/g) were present together, the oxidation was inhibited more effectively than by γ-tocopherol alone. Our findings suggest that there is potential antioxidant benefit in combining β-carotene and γ-tocopherol in food systems.

We demonstrate a quantum interconnect based on storage of light that enables the arbitrary shaping of the temporal properties of incoming coherent pulses. By shaping the retrieving control field, we achieve any predetermined temporal profile.

We present two quantum memory protocols for solids: a stopped light approach based on spectral hole burning and a storage in an atomic frequency comb. These procedures are well adapted to the rare-earth ion doped crystals. We carefully clarify the critical steps of both. In one case, we show that the slowing-down due to hole-burning is sufficient to produce a complete mapping of field into the atomic system. On the other side, we explain the storage and retrieval mechanism of the Atomic Frequency Comb protocol. These two critical stages of the protocols are implemented experimentally in Tm 3 + -doped yttrium–aluminum–garnet crystal.

One of the major advances needed to realize all-optical information processing of light is the ability to delay or coherently store and retrieve optical information in a rapidly tunable manner. In the classical domain, this optical buffering is expected to be a key ingredient to managing the flow of information over complex optical networks. Such a system also has profound implications for quantum information processing, serving as a long-term memory that can store the full quantum information contained in an optical pulse. Here we suggest a novel approach to light storage involving an optical waveguide coupled to an optomechanical crystal array, where light in the waveguide can be dynamically and coherently transferred into long-lived mechanical vibrations of the array. Under realistic conditions, this system is capable of achieving large bandwidths and storage/delay times in a compact, on-chip platform., 18 pages, 6 figures, 5 appendices

We propose a new approach for the storage of 8bit optical data bursts based on quasi-light-storage method. We achieved storage time of 100ns using conventional telecommunication components with the ability of fine and coarse tuning.

We investigate the evolution of a Zeeman coherence grating induced in a cold atomic cesium sample in the presence of an external magnetic field. The gratings are created in a three-beam light storage configuration using two quasi-collinear writing laser pulses and reading with a counterpropagating pulse after a variable time delay. The phase conjugated pulse arising from the atomic sample is monitored. Collapses and revivals of the retrieved pulse are observed for different polarizations of the laser beams and for different directions of the applied magnetic field. While magnetic field inhomogeneities are responsible for the decay of the coherent atomic response, a five-fold increase in the coherence decay time, with respect to no applied magnetic field, is obtained for an appropriate choice of the direction of the applied magnetic field. A simplified theoretical model illustrates the role of the magnetic field mean and its inhomogeneity on the collective atomic response., Comment: To appear in J. Phys. B

We present a theoretical study of the dynamics of a light pulse propagating through a multilayer system consisting of alternating blocks of electromagnetically induced transparency (EIT) media and vacuum.We study the effect of a dynamical modulation of the EIT control field on the shape of the wave packet. Interesting effects due to the group velocity mismatch at the interfaces are found. Modulation schemes that can be realized in ultracold atomic samples with standard experimental techniques are proposed and discussed. Calculations are performed using a modified slowly varying envelope approximation of the Maxwell-Bloch equations and are compared to an effective description based on a continuity equation for the polariton flow.

We propose an all-optical scheme to probe the dynamical correlations of a strongly interacting gas of ultracold atoms in an optical lattice potential. The proposed technique is based on a pump-and-probe scheme: a coherent light pulse is initially converted into an atomic coherence and later retrieved after a variable storage time. The efficiency of the proposed method to measure the two-time one-particle Green function of the gas is validated by numerical and analytical calculations of the expected signal for the two cases of a normal Fermi gas and a BCS superfluid state. Protocols to extract the superfluid gap and the full quasiparticle dispersions are discussed.

We experimentally demonstrate electromagnetically induced transparency and light storage with ultracold 87Rb atoms in a Mott insulating state in a three dimensional optical lattice. We have observed light storage times of about 240 ms, to our knowledge the longest ever achieved in ultracold atomic samples. Using the differential light shift caused by a spatially inhomogeneous far detuned light field we imprint a "phase gradient" across the atomic sample, resulting in controlled angular redirection of the retrieved light pulse., 4 pages, 4 figures

We experimentally demonstrate light storage and release in a four-level double-lambda atomic system of a Pr (3+):Y(2)SiO(5) crystal. Based on the technique of light storage, we realize optical information transfer between two light channels. The coherent optical information of a probe pulse stored in the crystal can be selectively released into two different light channels by varying the frequency and propagation direction of the switch-on control field.

We show analytically and numerically that the application, during the storage time, of an additional weak field connecting the lower levels (LLs) of a Lambda system can modify the spin coherence and the amplitude of the retrieved probe without causing distortion. The LL coupling field adds an additional phase-dependent term to the probe propagation equation. The retrieved probe is amplified when the total relative phase Phi=0 or pi and decreased when Phi=pi/2.

We experimentally and theoretically analyze the propagation of weak optical signal pulses under the conditions of electromagnetically induced transparency in hot Rb vapor, and study the effects of resonant four-wave mixing on light storage.

We introduced angular multiplexing in light storage via electromagnetically induced transparency in a Pr 3+ :Y 2 SiO 5 crystal. Multi-channel buffer memory and addressable all-optical routing were demonstrated by selectively reading out stored pulses without cross-talk between neighboring channels.