425 citations · 3.2k across the 81 of their papers we have counts for
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Superconducting flux qubit with ferromagnetic Josephson -junction operating at zero magnetic field
Sunmi Kim, Leonid V. Abdurakhimov, Duong Pham +6
Conventional superconducting flux qubits require the application of a precisely tuned magnetic field to set the operation point at half a flux quantum through the qubit loop, which…
Fabrication of Deep-Sub-Micrometer NbN/AlN/NbN Epitaxial Junctions on a Si Substrate
Wei Qiu, Hirotaka Terai
We have developed a novel fabrication process for ultra-small, full-epitaxial NbN Josephson junctions on a silicon (Si) substrate. A full-epitaxial NbN/AlN/NbN tri-layer was grown…
Nonreciprocal Terahertz Second Harmonic Generation in Superconducting NbN under Supercurrent Injection
Sachiko Nakamura, Kota Katsumi, Hirotaka Terai +1
Giant second-harmonic generation (SHG) in the terahertz (THz) frequency range is observed in a thin film of an s-wave superconductor NbN, where the time-reversal (-) a…
Infrared activation of the Higgs mode by supercurrent injection in superconducting NbN
Sachiko Nakamura, Yudai Iida, Yuta Murotani +3
Higgs mode in superconductors, i.e. the collective amplitude mode of the order parameter does not associate with charge nor spin fluctuations, therefore it does not couple to the e…
Polarization-resolved terahertz third-harmonic generation in a superconductor NbN: dominance of Higgs mode beyond the BCS approximation
Ryusuke Matsunaga, Naoto Tsuji, Kazumasa Makise +3
Recent advances in time-domain terahertz (THz) spectroscopy have unveiled that resonantly-enhanced strong THz third-harmonic generation (THG) mediated by the collective Higgs ampli…
Low-Filling-Factor Superconducting Single Photon Detector with High System Detection Efficiency
Taro Yamashita, Shigehito Miki, Hirotaka Terai +1
We designed, fabricated, and measured superconducting nanowire single-photon detectors (SSPDs) with low filling factor which achieve high system detection efficiency (SDE) and coun…
Higgs Amplitude Mode in BCS Superconductors NbTiN induced by Terahertz Pulse Excitation
Ryusuke Matsunaga, Yuki I. Hamada, Kazumasa Makise +4
Ultrafast responses of BCS superconductor Nb1-xTixN films in a nonadiabatic excitation regime were investigated by using terahertz (THz) pump-THz probe spectroscopy. After an insta…
Origin of intrinsic dark count in superconducting nanowire single-photon detectors
T. Yamashita, S. Miki, K. Makise +5
The origin of the decoherence in superconducting nanowire single-photon detectors, the so-called dark count, was investigated. We measured the direct-current characteristics and bi…