Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

International Crimean Conference Microwave and Telecommunication Technology

High-quality tunable superconducting circuit for MHz range

Evgeny A. Vopilkin, Alexey E. Parafin, Sergey A. Pavlov, L.I. Ponomarev, A. Yu. Ganitsev, A.S. Zhukov, V.V. Parshikov

Published Nov 13, 2002• 0 citations
Publisher

Abstract

The opportunity of fabrication of the high-quality (Q /spl sim/ 10/sup 5/) circuit mechanically tuneable in a wide frequency range for MHz applications is considered. The tuneable circuit consists of two single circuits made on YBaCuO films.
DOI
10.1109/crmico.2001.961617

Related papers

High-quality tunable superconducting circuit for MHz range

Vopilkin, Parafin, Павлов +4 more

International Crimean Conference Microwave and Telecommunication Technology•Jan 1, 2001•0 citations

Frequency-tunable superconducting resonators via nonlinear kinetic inductance

Michael R. Vissers, Johannes Hubmayr, Martin Sandberg +3 more

We have designed, fabricated, and tested a frequency-tunable high-Q superconducting resonator made from a niobium titanium nitride film. The frequency tunability is achieved by injecting a DC through a current-directing circuit into the nonlinear inductor whose kinetic inductance is current-dependent. We have demonstrated continuous tuning of the resonance frequency in a 180 MHz frequency range around 4.5 GHz while maintaining the high internal quality factor Qi > 180 000. This device may serve as a tunable filter and find applications in superconducting quantum computing and measurement. It also provides a useful tool to study the nonlinear response of a superconductor. In addition, it may be developed into techniques for measurement of the complex impedance of a superconductor at its transition temperature and for readout of transition-edge sensors.

arXiv:1507.05126•Applied Physics Letters•Aug 10, 2015•93 citations

Tunable High Q Superconducting Microwave Resonator

Z. Kim, Constantine P. Vlahacos, Jennifer E. Hoffman +9 more

Bulletin of the American Physical Society•Mar 21, 2011•0 citations

Superconducting nanostructures for counting of single photons in the infrared range

Чулкова Галина Меркурьевна, I. Milostnaya, Alexander A. Korneev +11 more

We present our studies on ultrafast superconducting single-photon detectors (SSPDs) based on ultrathin NbN nanostructures. Our SSPDs are patterned by electron beam lithography from 4-nm thick NbN film into meander-shaped strips covering square area of 10/spl times/10 /spl mu/m/sup 2/. The advances in the fabrication technology allowed us to produce highly uniform 100-120-nm-wide strips with meander filling factor close to 0.6. The detectors exploit a combined detection mechanism, where upon a single-photon absorption, an avalanche of excited hot electrons and the biasing supercurrent, jointly produce a picosecond voltage transient response across the superconducting nanostrip. The SSPDs are typically operated at 4.2 K, but they have shown that their sensitivity in the infrared radiation range can be significantly improved by lowering the operating temperature from 4.2 K to 2 K. When operated at 2 K, the SSPD quantum efficiency (QE) for visible light photons reaches 30-40%, which is the saturation value limited by optical absorption of our 4-nm-thick NbN film. For 1.55 /spl mu/m photons, QE was /spl sim/20% and decreases exponentially with the increase of the optical wavelength, but even at the wavelength of 6 /spl mu/m the detector remains sensitive to single photons and exhibits QE of about 10/sup -2/%. The dark (false) count rate at 2 K is as low as 2 /spl times/ 10/sup -4/ s/sup -1/, what makes our detector essentially a background-limited sensor. The very low dark-count rate results in the noise equivalent power (NEP) as low as 10/sup -18/ WHz/sup -1/2/ for the mid-infrared range (6 /spl mu/m). Further improvement of the SSPD performance in the mid-infrared range can be obtained by substituting NbN for the other, lower-T/sub c/ superconductors with the narrow superconducting gap and low quasiparticle diffusivity. The use of such materials will shift the cutoff wavelength towards the values even longer than 6 /spl mu/m.

CAOL . International Conference on Advanced Optoelectronics and Lasers•Jan 5, 2006•3 citations

A 10 GHz digital amplifier in an ultra-small-spread high-J/sub c/ Nb/Al-AlOx/Nb integrated circuit process

Anupama Bhat, Xiaofan Meng, Stephen R. Whiteley +2 more

We describe a Josephson amplifier fabricated in a high-J/sub c/ process, which is operational to speeds of at least 10 GHz, the highest reported for a voltage-state amplifier. The amplifier converts /spl sim/200 /spl mu/V digital signals to /spl sim/5 mV at 10 GHz and could be used as an interface between two superconducting systems. The bit-error-rate of the circuit was /spl sim/5/spl times/10/sup -12/ at 5 GHz, the lowest reported; bit-error-rate measurements at 10 GHz were not possible. A high-J/sub c/ process which was used to fabricate the amplifier was developed at UC Berkeley with extremely low I/sub c/ spreads; at /spl sim/9.4 kA/cm/sup 2/ /spl sigma/ as low as 0.6% was observed. At /spl sim/10 kA/cm/sup 2/, the typical junction linear dimensions are 1.5 /spl sim/ 2 /spl mu/m, sizes for which it is not possible-with available tools-to make reliable vias that are smaller than the junction. We use a nonplanarized junction process, where the via for contact of a wiring layer to a junction can be larger than the junction.

IEEE Transactions on Applied Superconductivity•Jun 1, 1999•26 citations

Tunable high Tc superconducting resonator using nonlinear equivalent inductance for Josephson junction

Hui‐Fen Huang, Junfa Mao

Physica C Superconductivity•Jun 3, 2003•3 citations
We have designed, fabricated, and tested a frequency-tunable high-Q superconducting resonator made from a niobium titanium nitride film. The frequency tunability is achieved by injecting a DC through a current-directing circuit into the nonlinear inductor whose kinetic inductance is current-dependent. We have demonstrated continuous tuning of the resonance frequency in a 180 MHz frequency range around 4.5 GHz while maintaining the high internal quality factor Qi > 180 000. This device may serve as a tunable filter and find applications in superconducting quantum computing and measurement. It also provides a useful tool to study the nonlinear response of a superconductor. In addition, it may be developed into techniques for measurement of the complex impedance of a superconductor at its transition temperature and for readout of transition-edge sensors.
We present our studies on ultrafast superconducting single-photon detectors (SSPDs) based on ultrathin NbN nanostructures. Our SSPDs are patterned by electron beam lithography from 4-nm thick NbN film into meander-shaped strips covering square area of 10/spl times/10 /spl mu/m/sup 2/. The advances in the fabrication technology allowed us to produce highly uniform 100-120-nm-wide strips with meander filling factor close to 0.6. The detectors exploit a combined detection mechanism, where upon a single-photon absorption, an avalanche of excited hot electrons and the biasing supercurrent, jointly produce a picosecond voltage transient response across the superconducting nanostrip. The SSPDs are typically operated at 4.2 K, but they have shown that their sensitivity in the infrared radiation range can be significantly improved by lowering the operating temperature from 4.2 K to 2 K. When operated at 2 K, the SSPD quantum efficiency (QE) for visible light photons reaches 30-40%, which is the saturation value limited by optical absorption of our 4-nm-thick NbN film. For 1.55 /spl mu/m photons, QE was /spl sim/20% and decreases exponentially with the increase of the optical wavelength, but even at the wavelength of 6 /spl mu/m the detector remains sensitive to single photons and exhibits QE of about 10/sup -2/%. The dark (false) count rate at 2 K is as low as 2 /spl times/ 10/sup -4/ s/sup -1/, what makes our detector essentially a background-limited sensor. The very low dark-count rate results in the noise equivalent power (NEP) as low as 10/sup -18/ WHz/sup -1/2/ for the mid-infrared range (6 /spl mu/m). Further improvement of the SSPD performance in the mid-infrared range can be obtained by substituting NbN for the other, lower-T/sub c/ superconductors with the narrow superconducting gap and low quasiparticle diffusivity. The use of such materials will shift the cutoff wavelength towards the values even longer than 6 /spl mu/m.
We describe a Josephson amplifier fabricated in a high-J/sub c/ process, which is operational to speeds of at least 10 GHz, the highest reported for a voltage-state amplifier. The amplifier converts /spl sim/200 /spl mu/V digital signals to /spl sim/5 mV at 10 GHz and could be used as an interface between two superconducting systems. The bit-error-rate of the circuit was /spl sim/5/spl times/10/sup -12/ at 5 GHz, the lowest reported; bit-error-rate measurements at 10 GHz were not possible. A high-J/sub c/ process which was used to fabricate the amplifier was developed at UC Berkeley with extremely low I/sub c/ spreads; at /spl sim/9.4 kA/cm/sup 2/ /spl sigma/ as low as 0.6% was observed. At /spl sim/10 kA/cm/sup 2/, the typical junction linear dimensions are 1.5 /spl sim/ 2 /spl mu/m, sizes for which it is not possible-with available tools-to make reliable vias that are smaller than the junction. We use a nonplanarized junction process, where the via for contact of a wiring layer to a junction can be larger than the junction.