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Nikoghosyan, A. S., Martirosyan, R. M., Hakhoumian, A. A., Makaryan, A. H., Tadevosyan, V. R., Goltsman, G. N., et al. (2018). Effect of absorption on the efficiency of THz radiation generation in a nonlinear crystal placed into a waveguide. Armenian J. Phys., 11(4), 257–262.
Abstract: The effect of THz radiation absorption on the efficiency of generation of coherent THz radiation in a nonlinear optical crystal placed into a metal rectangular waveguide is studied. The efficiency of the nonlinear conversion of optical laser radiation to the THz band is also a function of the phase-matching (PM) condition inside the nonlinear crystal. The method of partial filling of a metal waveguide with a nonlinear optical crystal is used to ensure phase matching. Phase matching was obtained by the proper choice of the thickness of the nonlinear crystal, namely the degree of partial filling of the waveguide. We have studied the THz radiation attenuation caused by the losses in both the metal walls of the waveguide and in the crystal, taking into account the dimension of the cross section of the waveguide, the degree of partial filling and its dielectric constant.
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Kardakova, A. I., Coumou, P. C. J. J., Finkel, M. I., Morozov, D. V., An, P. P., Goltsman, G. N., et al. (2015). Electron–phonon energy relaxation time in thin strongly disordered titanium nitride films. IEEE Trans. Appl. Supercond., 25(3), 1–4.
Abstract: We have measured the energy relaxation times from the electron bath to the phonon bath in strongly disordered TiN films grown by atomic layer deposition. The measured values of τ eph vary from 12 to 91 ns. Over a temperature range from 3.4 to 1.7 K, they follow T -3 temperature dependence, which are consistent with values of τ eph reported previously for sputtered TiN films. For the most disordered film, with an effective elastic mean free path of 0.35 nm, we find a faster relaxation and a stronger temperature dependence, which may be an additional indication of the influence of strong disorder on a superconductor.
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Komrakova, S., Javadzade, J., Vorobyov, V., Bolshedvorskii, S., Soshenko, V., Akimov, A., et al. (2018). On-chip controlled placement of nanodiamonds with a nitrogen-vacancy color centers (NV). In J. Phys.: Conf. Ser. (Vol. 1124, 051046 (1 to 4)).
Abstract: Here we studied the fabrication technique of a kilopixel array of nanodiamonds with a nitrogen-vacancy color centers (NV) on top of the chip and measured the second-order correlation function deep, clearly demonstrated the presence of single-photon sources. The controlled position of nanodiamonds, determined from the measurement of second-order correlation fiction, was realize, as well as the yield of optimized technique equals 12.5% is shown.
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Elezov, M. S., Scherbatenko, M. L., Sych, D. V., & Goltsman, G. N. (2018). Active and passive phase stabilization for the all-fiber Michelson interferometer. In J. Phys.: Conf. Ser. (Vol. 1124, 051014 (1 to 5)).
Abstract: We put forward two methods for phase stabilization in the all-fiber Michelson interferometer. To perform passive phase stabilization, we use a heat bath for all fibers and electro-optical components, and put the interferometer in a hermetic case. To perform active phase stabilization, we monitor output power of the interferometer and develop an electronic feedback control. The phase stabilization methods enable stable interference pattern for several minutes, and can be helpful for the development of the optimal quantum receiver for coherent signals.
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Matyushkin, Y. E., Gayduchenko, I. A., Moskotin, M. V., Goltsman, G. N., Fedorov, G. E., Rybin, M. G., et al. (2018). Graphene-layer and graphene-nanoribbon FETs as THz detectors. In J. Phys.: Conf. Ser. (Vol. 1124, 051054).
Abstract: We report on detection of sub-THz radiation (129-430 GHz) using graphene based asymmetric field-effect transistor (FET) structures with different channel geometry: monolayer graphene, graphene nanoribbons. In all devices types we observed the similar trends of response on sub-THz radiation. The response fell with increasing frequency at room temperature, but increased with increasing frequency at 77 K. Our calculations show that the change in the trend of the frequency dependence at 77 K is associated with the appearance of plasma waves in the graphene channel. Unusual properties of p-n junctions in graphene are highlighted using devices of special geometry.
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