TY - JOUR
T1 - A measurement method for responsivity of microwave kinetic inductance detector by changing power of readout microwaves
AU - Kutsuma, H.
AU - Hattori, M.
AU - Koyano, R.
AU - Mima, S.
AU - Oguri, S.
AU - Otani, C.
AU - Taino, T.
AU - Tajima, O.
N1 - Funding Information:
This work was supported by the JRA program in RIKEN and Grants-in-Aid for Scientific Research from The Ministry of Education, Culture, Sports, Science and Technology, Japan (KAKENHI Grant Nos. 15H05743, 16J09435, 18H05539, 15K13491, 16H00874, and R2804). We thank Shunsuke Honda, Taketo Nagasaki, and Junya Suzuki for useful discussions. We thank Mr. Noboru Furukawa, Advanced Technology Center of National Astronomical Observatory of Japan, and Advanced Manufacturing Support Team of RIKEN.
Publisher Copyright:
© 2019 Author(s).
PY - 2019/7/15
Y1 - 2019/7/15
N2 - Superconducting detectors are a modern technology applied in various fields. The microwave kinetic inductance detector (MKID) is one of the cutting-edge superconducting detectors. It is based on the principle of a superconducting resonator circuit. A radiation entering the MKID breaks the Cooper pairs in the superconducting resonator, and the intensity of the radiation is detected as a variation of the resonant condition. Therefore, calibration of the detector responsivity, i.e., the variation of the resonant phase with respect to the number of Cooper-pair breaks (quasiparticles), is important. We propose a method for responsivity calibration. Microwaves used for the detector readout locally raise the temperature in each resonator, which increases the number of quasiparticles. Since the magnitude of the temperature rise depends on the power of readout microwaves, the number of quasiparticles also depends on the power of microwaves. By changing the power of the readout microwaves, we simultaneously measure the phase difference and lifetime of quasiparticles. We calculate the number of quasiparticles from the measured lifetime and by using a theoretical formula. This measurement yields a relation between the phase responses as a function of the number of quasiparticles. We demonstrate this responsivity calibration using the MKID maintained at 285 mK. We also confirm the consistency between the results obtained using this method and conventional calibration methods in terms of the accuracy.
AB - Superconducting detectors are a modern technology applied in various fields. The microwave kinetic inductance detector (MKID) is one of the cutting-edge superconducting detectors. It is based on the principle of a superconducting resonator circuit. A radiation entering the MKID breaks the Cooper pairs in the superconducting resonator, and the intensity of the radiation is detected as a variation of the resonant condition. Therefore, calibration of the detector responsivity, i.e., the variation of the resonant phase with respect to the number of Cooper-pair breaks (quasiparticles), is important. We propose a method for responsivity calibration. Microwaves used for the detector readout locally raise the temperature in each resonator, which increases the number of quasiparticles. Since the magnitude of the temperature rise depends on the power of readout microwaves, the number of quasiparticles also depends on the power of microwaves. By changing the power of the readout microwaves, we simultaneously measure the phase difference and lifetime of quasiparticles. We calculate the number of quasiparticles from the measured lifetime and by using a theoretical formula. This measurement yields a relation between the phase responses as a function of the number of quasiparticles. We demonstrate this responsivity calibration using the MKID maintained at 285 mK. We also confirm the consistency between the results obtained using this method and conventional calibration methods in terms of the accuracy.
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U2 - 10.1063/1.5110692
DO - 10.1063/1.5110692
M3 - Article
AN - SCOPUS:85069519830
VL - 115
JO - Applied Physics Letters
JF - Applied Physics Letters
SN - 0003-6951
IS - 3
M1 - 032603
ER -