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Yuri V. Panfilov

Publications and source records attributed to Yuri V. Panfilov.

5 recordsLinked to original sources

Superconducting single-photon detectors for integrated quantum photonics

Single-photon detection possibility is a fundamental requirement for quantum technologies, including communication, computing and sensing. To achieve scalability and practical deployment, increasing attention is being directed toward integration of detectors with photonic integrated circuits, which offer compactness and compatibility with mass production. Superconducting nanowire single-photon detectors have emerged as the leading solution, combining near-unity efficiency, high temporal performance and the ability to be embedded across a wide range of photonic material platforms. In this review we trace the development of integrated superconducting nanowire single-photon detectors from early demonstrations to recent advances, outlining the progress in device architectures, material engineering and integration strategies. We also discuss performance benchmarks, emerging alternative designs, the future opportunities and challenges for this rapidly evolving field.

physics.optics↗

An engineering guide to superconducting quantum circuit shielding

In this review, we provide a practical guide on protection of superconducting quantum circuits from broadband electromagnetic and infrared-radiation noise by using cryogenic shielding and filtering of microwave lines. Recently, superconducting multi-qubit processors demonstrated quantum supremacy and quantum error correction below the surface code threshold. However, the decoherence-induced loss of quantum information still remains a challenge for more than 100 qubit quantum computing. Here, we review the key aspects of superconducting quantum circuits protection from stray electromagnetic fields and infrared radiation, namely, multilayer shielding design, materials, filtering of the fridge lines and attenuation, cryogenic setup configurations, and methods for shielding efficiency evaluation developed over the last 10 years. In summary, we make recommendations for creation of an efficient and compact shielding system as well as microwave filtering for a large-scale superconducting quantum systems.

quant-ph↗

Integrated Electro-Optic Absorption Modulator for Silicon Nitride Platform

Silicon nitride (SiN) is currently the most prominent platform for photonics at visible and near-IR wavelength bandwidth. However, realizing fast electro-optic (EO) modulators, the key components of any integrated optics platform, remains challenging in SiN. Recently, transparent conductive oxides (TCO) have emerged as a promising platform for photonic integrated circuits. Here we make an important step towards exceeding possibilities of both platforms, reporting for the first-time high-speed ITO electro-optic modulators based on silicon nitride waveguides. The insertion losses of 5.7 dB and bandwidth of about 1 GHz are shown for 300 nm-thickness SiN waveguide platform with 9.3-um-length hybrid waveguide. The fabrication process of devices requires only standard clean room tools, is repeatable and compatible with the CMOS technology. Simulation results of optimized device designs indicate that further improvement is possible and offer promising opportunities towards silicon nitride photonic computation platforms based on ITO.

physics.optics↗

Wafer-scale uniformity improvement of Dolan-bridge Josephson junction by shadow evaporation bias correction

One of the practical limitations of solid-state superconducting quantum processors technology is frequency crowding due to low qubits fabrication reproducibility. Josephson junction 100 nm-scale nonlinear inductance of the qubits still suffers from Dolan-bridge shadow evaporation process. Here, we report on a robust wafer-scale Al/AlOx/Al Dolan-bridge Josephson junction (JJ) process using preliminary shadow evaporation bias resist mask correction and comprehensive oxidation optimization. We introduce topology correction model for two-layer resist mask biasing at a wafer-scale, which takes into account an evaporation source geometry. It results in Josephson junction area variation coefficient improvement down to 1.1% for the critical dimensions from 130x170 nm2 to 130x670 nm2 over 70x70 mm2 (49 cm2) wafer working area. Next, we investigate JJ oxidation process (oxidation method, pressure and time) and its impact on a room temperature resistance reproducibility. Finally, we combine both shadow evaporation bias correction and oxidation best practices for 4-inch wafers improving room temperature resistance variation coefficient down to 6.0/5.2/4.1% for 0.025 μm2 JJ area and 4.0/3.4/2.3% for 0.090 μm2 JJ area for 49/25/16 cm2 wafer working area correspondingly. The proposed model and oxidation method can be useful for robust wafer-scale superconducting quantum processors fabrication.

quant-ph↗

Sputtered NbN Films for Ultrahigh Performance Superconducting Nanowire Single-Photon Detectors

Nowadays ultrahigh performance superconducting nanowire single-photon detectors are the key elements in a variety of devices from biological research to quantum communications and computing. Accurate tuning of superconducting material properties is a powerful resource for fabricating single-photon detectors with a desired properties. Here, we report on the major theoretical relations between ultrathin niobium nitride (NbN) films properties and superconducting nanowire single-photon detectors characteristics, as well as ultrathin NbN films properties dependence on reactive magnetron sputtering recipes. Based on this study we formulate the exact requirements to ultrathin NbN films for ultrahigh performance superconducting nanowire single-photon detectors. Then, we experimentally study ultrathin NbN films properties (morphology, crystalline structure, critical temperature, sheet resistance) on silicon, sapphire, silicon dioxide and silicon nitride substrates sputtered with various recipes. We demonstrate ultrathin NbN films (obtained with more than 100 films deposition) with a wide range of critical temperature from 2.5 to 12.1 K and sheet resistance from 285 to 2000 ~$Ω$/sq, as well as investigate a sheet resistance evolution over for more than 40\% within two years. Finally, we found out that one should use ultrathin NbN films with specific critical temperature near 9 K and sheet resistance of 400 ~$Ω$/sq for ultrahigh performance SNSPD.

cond-mat.supr-con↗