Multilayer Bolometric Structures for Efficient Wideband Communication Signal Reception

Amari P., Kozlov S., Recoba-Pawlowski E., Velluire-Pellat Z., Jouan A., Couëdo F., Ulysse C., Briatico J., Roditchev D., Bergeal N., Lesueur J., Feuillet-Palma C.

The realization of superconducting single-photon detectors operating above the liquid-helium temperature is currently the focus of intense research efforts. Here, we present the fabrication of ultraclean encapsulated nanowires from commercially available thin films of $\mathrm{YBa}$${}_{2}$$\mathrm{Cu}$${}_{3}$$\mathrm{O}$${}_{7\ensuremath{-}\ensuremath{\delta}}$ by high-energy oxygen-ion irradiation. The structured nanowires, ranging from 0.1 to $5\phantom{\rule{0.2em}{0ex}}\text{\ensuremath{\mu}}\mathrm{m}$ in width, exhibit sharp resistive transitions to the superconducting state above 85 K. The $I$-$V$ characteristics reveal that the evolution from the superconducting to the normal state shows a large voltage jump in the volt range. This demonstrates that the entire nanowire transits---a prerequisite for the development of a hot spot upon absorption of a single photon. Our results pave the way for the fabrication of $\mathrm{YBa}$${}_{2}$$\mathrm{Cu}$${}_{3}$$\mathrm{O}$${}_{7\ensuremath{-}\ensuremath{\delta}}$-based scalable superconducting single-photon-detection devices.

Milul O., Guttel B., Goldblatt U., Hazanov S., Joshi L.M., Chausovsky D., Kahn N., Çiftyürek E., Lafont F., Rosenblum S.

A superconducting cavity qubit with coherence time an order of magnitude larger than the state of the art is demonstrated, showing the storage of a Schr\"odinger cat state with a record size of 1024 photons.

Velluire Pellat Z., Maréchal E., Moulonguet N., Saïz G., Ménard G.C., Kozlov S., Couëdo F., Amari P., Medous C., Paris J., Hostein R., Lesueur J., Feuillet-Palma C., Bergeal N.

AbstractSuperconducting microwave resonators are crucial elements of microwave circuits, offering a wide range of potential applications in modern science and technology. While conventional low-T$$_c$$ c superconductors are mainly employed, high-T$$_c$$ c cuprates could offer enhanced temperature and magnetic field operating ranges. Here, we report the realization of $$\textrm{YBa}_2\textrm{Cu}_3\textrm{O}_{7-\delta }$$ YBa 2 Cu 3 O 7 - δ superconducting coplanar waveguide resonators, and demonstrate a continuous evolution from a lossy undercoupled regime, to a lossless overcoupled regime by adjusting the device geometry, in good agreement with circuit model theory. A high-quality factor resonator was then used to perform electron spin resonance measurements on a molecular spin ensemble across a temperature range spanning two decades. We observe spin-cavity hybridization indicating coherent coupling between the microwave field and the spins in a highly cooperative regime. The temperature dependence of the Rabi splitting and the spin relaxation time point toward an antiferromagnetic coupling of the spins below 2 K. Our findings indicate that high-Tc superconducting resonators hold great promise for the development of functional circuits. Additionally, they suggest novel approaches for achieving hybrid quantum systems based on high-T$$_c$$ c superconductors and for conducting electron spin resonance measurements over a wide range of magnetic fields and temperatures.

Dryazgov M., Korneeva Y., Korneev A.

We report the development of photon-number-resolving superconducting single-photon detector with micron-scale $\mathrm{Nb}\mathrm{N}$ strips. The detector is designed as serial meander-shaped strips with resistors connected in parallel to each strip. We investigate the performance of the detectors comprising of 5--14 strips with the widths in the range $0.3$--$1\phantom{\rule{0.2em}{0ex}}\text{\ensuremath{\mu}}\mathrm{m}$ and covering an area as large as $70\ifmmode\times\else\texttimes\fi{}70\phantom{\rule{0.2em}{0ex}}\text{\ensuremath{\mu}}{\mathrm{m}}^{2}$ making it feasible for coupling to multimode fibers. We demonstrate resolution of up to six photons and analyze the sources of errors in photon-number resolution.

Charaev I., Bandurin D.A., Bollinger A.T., Phinney I.Y., Drozdov I., Colangelo M., Butters B.A., Taniguchi T., Watanabe K., He X., Medeiros O., Božović I., Jarillo-Herrero P., Berggren K.K.

The detection of individual quanta of light is important for quantum communication, fluorescence lifetime imaging, remote sensing and more. Due to their high detection efficiency, exceptional signal-to-noise ratio and fast recovery times, superconducting-nanowire single-photon detectors (SNSPDs) have become a critical component in these applications. However, the operation of conventional SNSPDs requires costly cryocoolers. Here we report the fabrication of two types of high-temperature superconducting nanowires. We observe linear scaling of the photon count rate on the radiation power at the telecommunications wavelength of 1.5 μm and thereby reveal single-photon operation. SNSPDs made from thin flakes of Bi2Sr2CaCu2O8+δ exhibit a single-photon response up to 25 K, and for SNSPDs from La1.55Sr0.45CuO4/La2CuO4 bilayer films, this response is observed up to 8 K. While the underlying detection mechanism is not fully understood yet, our work expands the family of materials for SNSPD technology beyond the liquid helium temperature limit and suggests that even higher operation temperatures may be reached using other high-temperature superconductors. Superconducting single-photon detectors are critical for quantum communication, fluorescence lifetime imaging and remote sensing, but commonly operate at very low temperatures. Now, high-temperature cuprate superconducting nanowires enable single-photon detection up to 25 K.

Yakovlev D.S., Nazhestkin I.A., Ismailov N.G., Egorov S.V., Antonov V.N., Gurtovoi V.L.

We study operation of a superconducting quantum interference devices (SQUIDs) based on a new bilayer material. They can be used for the ultra-sensitive detection of magnetic momentum at temperatures down to milliKelvin range. Typically, thermal origin hysteresis of the symmetric SQUID current-voltage curves limits operating temperatures to T>0.6Tc. We used a new bilayer material for SQUID fabrication, namely proximity-coupled superconductor/normal-metal (S/N) bilayers (aluminum 25 nm / platinum 5 nm). Because of the 5 nm Pt-layer, Al/Pt devices show nonhysteretic behavior in a broad temperature range from 20 mK to 0.8 K. Furthermore, the Al/Pt bilayer devices demonstrate an order of magnitude lower critical current compared to the Al devices, which decreases the screening parameter (βL) and improves the modulation depth of the critical current by magnetic flux. Operation at lower temperatures reduces thermal noise and increases the SQUID magnetic field resolution. Moreover, we expect strong decrease of two-level fluctuators on the surface of aluminum due to Pt-layer oxidation protection and hence significant reduction of the 1/f noise. Optimized geometry of Al/Pt symmetric SQUIDs is promising for the detection of single-electron spin flip.

Bogatskaya A.V., Klenov N.V., Popov A.M., Schegolev A.E., Titovets P.A., Tereshonok M.V.

We examine the effect of resonant absorption of electromagnetic signals in a silicon semiconductor plasma layer when the dielectric plate is placed behind it both experimentally and numerically. It is shown that such plate acts as a dielectric resonator and can significantly increase the electromagnetic energy absorption in the semiconductor for certain frequencies determined by the dielectric plate parameters. Numerical modelling of the effect is performed under the conditions of conducted experiment. The numerical results are found to be in qualitative agreement with experimental ones. This study confirms the proposed earlier method of increasing the efficiency of bolometric-type detectors of electromagnetic radiation.

Miao W., Li F., Luo Q., Wang Q., Zhong J., Wang Z., Zhou K., Ren Y., Zhang W., Li J., Shi S., Yu C., He Z., Liu Q., Feng Z.

Graphene is an attractive material for terahertz (THz) detectors due to its unique properties of extremely weak electron-phonon interaction and small electronic heat capacity. In this paper, we demonstrate a lens-antenna-coupled THz detector based on a diffusive superconductor-graphene-superconductor (SGS) junction, which has a sharp resistive transition at 1.4 K due to the proximity Josephson coupling. The SGS Josephson detector, measured with a dc superconducting quantum interference device (SQUID) readout, exhibits an electrical noise equivalent power (NEP) as low as 5 × 10 −17 W/Hz 0.5 at 0.1 K, which is still limited by the readout noise. Furthermore, the optical performance of the SGS Josephson detector is measured with a cryogenic blackbody radiation source, giving an optical NEP of 2.5–5 × 10 −16 W/Hz 0.5 at 1.4 THz in the temperature range from 0.1 K to 0.6 K.

Lita A.E., Reddy D.V., Verma V.B., Mirin R.P., Nam S.W.

Single-photon detectors based on superconducting thin films have become a viable class of technologies for widespread usage in quantum optics. In this tutorial paper we introduce the key performance metrics required of them for quantum information processing and related fields. We review the latest records achieved by such devices, study technical details regarding recent improvements in superconducting nanowire detectors and transition-edge sensors, and present representative applications in cutting-edge research areas that benefit from these advances.

Lubsanov V., Gurtovoi V., Semenov A., Glushkov E., Antonov V., Astafiev O.

Abstract In this work, we develop and study superconducting materials for a broadband microwave single-photon detector for wide-range applications in superconducting quantum devices. Ideal materials of this type should have a superconducting gap of the order of 10 GHz (0.2 K), and possess a normal sheet resistance of the order of 50  Ω . We find that Ti/Pt bilayers are good candidates: it enables to vary the superconducting transition temperature in a wide range, from 0.1 to 0.4 K, and the sheet resistance in the range from 10 to 50  Ω . We present a proof-of-principle demonstration of a low-level microwave power detector based on a nanobridge made of a designed Ti/Pt bilayer. The response to the absorbed microwave power is consistent with the picture of the kinetic inductance detection in superconductors. The extracted response time corresponds to the recombination of quasiparticles with the emission of a photon to the microwave line.

Xu X., Rajteri M., Li J., Zhang S., Pepe C., Chen J., Gao H., Li Q., Li W., Li X., Zhang M., Ouyang Y., Wang X.

Transition-edge sensors (TES) are remarkable superconducting devices for a wide range of radiation detection with the ability of both energy resolution and counting photons. For the detection of single photons at telecom wavelength, optical Ti/Au bilayer TESs are fabricated and characterized. The superconducting transition temperature (Tc) of the Ti/Au films is effectively tuned from 162 to 72 mK by increasing the relative thickness ratio between the Au and Ti layer. The sensitive area is 20 μm × 20 μm, on which an SiO2/SiNx antireflection structure is coated by an ICP-PECVD process. The TES device shows an energy resolution of 0.19 eV and can discriminate up to 36 incident photons, with an effective time constant around 107 µs at 95 mK.

Pankratov A.L., Gordeeva A.V., Revin L.S., Ladeynov D.A., Yablokov A.A., Kuzmin L.S.

Here, we experimentally test the applicability of an aluminium Josephson junction of a few micrometers size as a single photon counter in the microwave frequency range. We have measured the switching from the superconducting to the resistive state through the absorption of 10 GHz photons. The dependence of the switching probability on the signal power suggests that the switching is initiated by the simultaneous absorption of three and more photons, with a dark count time above 0.01 s.

Pankratov A.L., Revin L.S., Gordeeva A.V., Yablokov A.A., Kuzmin L.S., Il’ichev E.

AbstractThe major task of detecting axions or axion-like particles has two challenges. On the one hand, the ultimate sensitivity is required, down to the energy of a single microwave photon of the yoctojoule range. On the other hand, since the detected events are supposed to be rare, the dark count rate of the detector must be extremely low. We show that this trade-off can be approached due to the peculiar switching dynamics of an underdamped Josephson junction in the phase diffusion regime. The detection of a few photons’ energy at 10 GHz with dark count time above 10 s and the efficiency close to unity was demonstrated. Further enhancements require a detailed investigation of the junction switching dynamics.

Bogatskaya A.V., Klenov N.V., Popov A.M., Schegolev A.E., Titovets P.A., Tereshonok M.V.

Abstract We present an experimental study of the effect of resonant tunnelling of radio frequency signals through a silicon semiconductor plasma sheet with supercritical electron density. The resonance effect appears when a dielectric plate is placed behind the plasma sheet and is determined by the dielectric parameters. The numerical modelling of the effect under the experimental conditions was implemented and compared with the experimental data. The features of the wave resonant tunnelling effect in the case of a high-collisional semiconductor plasma were analyzed. This study confirms the proposed earlier method of overcoming the radiocommunication blackout problem.

Hadi Badri S., Gilarlue M.M., SaeidNahaei S., Kim J.S.

We present and numerically investigate a high-quality factor (high-Q) meta-atom with Fano resonance. Numerical simulations indicate that the designed meta-atom has a single sharp Fano resonance in the 1350–1750 1/cm range. Moreover, the frequency of the single resonance can be tuned in this frequency range by scaling the meta-atom. We exploit these properties to design a pixelated metasurface for spectrometer-less molecular fingerprint retrieval. The proposed meta-atom with an average quality factor of 2000 makes it possible to decrease the scaling step of metapixels without introducing resonance overlap between the metapixels, leading to higher precision in label-free and nondestructive identification of molecular fingerprints.

Nazhestkin I.A., Bakurskiy S.V., Neilo A.A., Tarasova I.E., Ismailov N.G., Gurtovoi V.L., Egorov S.V., Lisitsyn S.A., Stolyarov V.S., Antonov V.N., Ryazanov V.V., Kupriyanov M.Y., Soloviev I.I., Klenov N.V., Yakovlev D.S.

The transport properties of a nanobridge superconducting quantum interference device made of Al/Pt bilayer have been studied. Measurement and approximation of the voltage‐field dependencies allow to estimate the inductance of the structure. It is found that this value significantly exceeds the expected geometric inductance and exhibits an atypical temperature dependence. To explain this effect, a microscopic model of electron transport in SN bilayers is developed, considering the proximity effect, and the available regimes of the current distribution are described. The measured properties may be indicative of the formation of high‐resistance aluminum with high values of kinetic inductance during the fabrication of Al/Pt bilayers.

Liu B., Yan C., Ren Q., Li W., Ma W., Liu Z., Zhang H., Zhu H., Zhang Z., Zhao W., Wang Y.