Elmanov, I., Elmanova, A., Kovalyuk, V., An, P., & Goltsman, G. (2020). Integrated contra-directional coupler for NV-centers photon filtering. In Proc. 32-nd EMSS (pp. 354–360).
Abstract: We modelled an integrated optical contra-directional coupler on silicon nitride platform. Performance of the filter was studied depending on different parameters, including the grating period and the height of teeth of the Bragg grating near 637 nm operation wavelength. The obtained results can be used for a design and fabrication of quantum photonic integrated circuits with on-chip single-photon NV-centers in nanodiamonds.
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Elmanov, I., Elmanova, A., Kovalyuk, V., An, P., & Goltsman, G. (2020). Silicon nitride photonic crystal cavity coupled with NV-centers in nanodiamonds. In Proc. 32-nd EMSS (pp. 344–348).
Abstract: The development of integrated quantum photonics requires a high efficient excitation and coupling of a single photon source with on-chip devices. In this paper, we show our results of modelling for high-Q photonic crystal cavity, optimized for zero phonon line emission of NV-centers in nanodiamonds. Modelling was performed for the silicon nitride platform and obtained a quality factor equals to 6136 at 637 nm wavelength.
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Korneev, A., Korneeva, Y., Florya, I., Elezov, M., Manova, N., Tarkhov, M., et al. (2011). Recent advances in superconducting NbN single-photon detector development. In Proc. SPIE (Vol. 8072, 807202 (1 to 10)).
Abstract: Superconducting single-photon detector (SSPD) is a planar nanostructure patterned from 4-nm-thick NbN film deposited on sapphire substrate. The sensitive element of the SSPD is 100-nm-wide NbN strip. The device is operated at liquid helium temperature. Absorption of a photon leads to a local suppression of superconductivity producing subnanosecond-long voltage pulse. In infrared (at 1550 nm and longer wavelengths) SSPD outperforms avalanche photodiodes in terms of detection efficiency (DE), dark counts rate, maximum counting rate and timing jitter. Efficient single-mode fibre coupling of the SSPD enabled its usage in many applications ranging from single-photon sources research to quantum cryptography. Recently we managed to improve the SSPD performance and measured 25% detection efficiency at 1550 nm wavelength and dark counts rate of 10 s-1. We also improved photon-number resolving SSPD (PNR-SSPD) which realizes a spatial multiplexing of incident photons enabling resolving of up to 4 simultaneously absorbed photons. Another improvement is the increase of the photon absorption using a λ/4 microcavity integrated with the SSPD. And finally in our strive to increase the DE at longer wavelengths we fabricated SSPD with the strip almost twice narrower compared to the standard 100 nm and demonstrated that in middle infrared (about 3 μm wavelength) these devices have DE several times higher compared to the traditional SSPDs.
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Kuzin, A., Elmanov, I., Kovalyuk, V., An, P., & Goltsman, G. (2020). Silicon nitride focusing grating coupler for input and output light of NV-centers. In Proc. 32-nd EMSS (pp. 349–353).
Abstract: Here we presented the numerical results for the calculation of focusing grating coupler efficiency in the visible wavelength range. Using the finite element method, the optimal geometric parameters, including filling factor and grating period for a central wavelength of 637 nm, were found. Obtained results allow to input/output single-photon radiation from NV-centers, and can be used for research and development of a scalable on-chip quantum optical computing.
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