Elmanova, A., Elmanov, I., Komrakova, S., Golikov, A., Javadzade, J., Vorobyev, V., et al. (2019). Integration of nanodiamonds with NV-centers on optical silicon nitride structures. In EPJ Web Conf. (Vol. 220, 03013).
Abstract: In this work we had developed optical structures from silicon nitride for further integration of the nanodiamonds containing NV-centers with them. We have introduced method of the nanodiamonds solution application on the substrates. The work has practical meaning in nanophotonics sphere and in development of optical devices with single-photon sources.
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Elezov, M., Scherbatenko, M., Sych, D., Goltsman, G., Arakelyan, S., Evlyukhin, A., et al. (2019). Towards the fiber-optic Kennedy quantum receiver. In EPJ Web Conf. (Vol. 220, 03011 (1 to 2)).
Abstract: We consider practical aspects of using standard fiber-optic elements and superconducting nanowire single-photon detectors for the development of a practical quantum receiver based on the Kennedy scheme. Our receiver allows to discriminate two phase-modulated coherent states of light at a wavelength of 1.5 microns in continuous mode with bit rate 200 Kbit/s and error rate about two times below the standard quantum limit.
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Tiulina, V., Iomdina, E., Goltsman, G., Seliverstov, S., Sianosyan, A., Teplyakova, K., et al. (2019). UVB promotes the initiation of uveitic inflammatory and changes in thehydration of the cornea in vivo (Vol. 9).
Abstract: Recently, active research has been conducted in the field of terahertz (THz) scanning of human tissues for noninvasive determination of their hydration level, which haves hown high diagnostic efficiency of this technology in various pathological conditions. Recently, we have developed a laboratory model of the facility for monitoring the state of the water balance of the cornea using THz scanning in vivo, which opens up the possibility of applying this approach in ophthalmology. The aim of the work wasto compare the results of the THz scan of the cornea with its clinical changes using the example of an experimental model of the UV induced keratouveitis. Anexperimental study, which included a comprehensive assessment of clinical changes in the cornea of rabbits during keratouveitis induction, revealed a decrease in the stability of the tear film, pathological changes in the corneal epithelium and stroma, as well as its anatomical and optical parameters. Comparison of data obtained in the THz scan of the cornea with tears production, optical coherence tomography and confocal microscopy showed their consistency in all observation periods, which allows us to conclude that the developed laboratory setup works and the feasibility of further research to promote the corneal hydration evaluation technology in clinical practice. Acknowledgements: Research was funded by the RSF, grant number 161500255.
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Polyakova, M., Semenov, A. V., Kovalyuk, V., Ferrari, S., Pernice, W. H. P., & Gol'tsman, G. N. (2019). Protocol of measuring hot-spot correlation length for SNSPDs with near-unity detection efficiency. IEEE Trans. Appl. Supercond., 29(5), 1–5.
Abstract: We present a simple quantum detector tomography protocol, which allows, without ambiguities, to measure the two-spot detection efficiency and extract the hot-spot interaction length of superconducting nanowire single photon detectors (SNSPDs) with unity intrinsic detection efficiency. We identify a significant parasitic contribution to the measured two-spot efficiency, related to an effect of the bias circuit, and find a way to rule out this contribution during data post-processing and directly in the experiment. From the data analysis for waveguide-integrated SNSPD, we find signatures of the saturation of the two-spot efficiency and hot-spot interaction length of order of 100 nm.
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Nikogosyan, A. S., Martirosyan, R. M., Hakhoumian, A. A., Makaryan, A. H., Tadevosyan, V. R., Goltsman, G. N., et al. (2019). Effect of absorption on the efficiency of terahertz radiation generation in the metal waveguide partially filled with nonlinear crystal LiNbO3, DAST or ZnTe. J. Contemp. Phys., 54(1), 97–104.
Abstract: The influence of terahertz (THz) radiation absorption on the efficiency of generation of coherent THz radiation in the system ‘nonlinear-optical crystal partially filling the cross section of a rectangular metal waveguide’ has been investigated. The efficiency of the nonlinear frequency conversion of optical laser radiation to the THz range depends on the loss in the system and the fulfillment of the phase-matching (FM) condition in a nonlinear crystal. The method of partially filling of a metal waveguide with a nonlinear optical crystal is used to ensure phase matching. The phase matching is achieved by numerical determination of the thickness of the nonlinear crystal, that is the degree of partial filling of the waveguide. The attenuation of THz radiation caused by losses both in the metal walls of the waveguide and in the crystal was studied, taking into account the dimension of the cross section of the waveguide, the degree of partial filling, and the dielectric constant of the crystal. It is shown that the partial filling of the waveguide with a nonlinear crystal results in an increase in the efficiency of generation of THz radiation by an order of magnitude, owing to the decrease in absorption.
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