Studies on Terahertz Photon Counting Detectors with Low-Leakage SIS Junctions
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We plan to realize a fast terahertz photon counting detector. The detector may resolve each photon signal from the source and enable us to introduce “photon statistics,” which will be a new measure for terahertz astronomy and astrophysics. An SIS junction with Nb/Al/AlOx/Al/Nb is considered for this detector, which should incorporate low leakage current of 1 pA. We have successfully developed an SIS junction to satisfy this requirement. The bandwidth is limited, while it is sufficient for laboratory experiments. We have designed an antenna-coupled SIS detector incorporating the low-leakage SIS junction for photon counting experiments. Additionally, the photo-response of the SIS junction is measured to discuss the photon counting capability in combination with the fast readout system.
KeywordsSuperconducting tunnel junction Terahertz detector Photon counting
Special thanks to Dr. Takafumi Kojima, Dr. Tom Nitta, Dr. Wenlei Shan, and Dr. Tai Oshima for fruitful discussions and their supports. This research was financially supported by the Matsuo Foundation, ISAS/JAXA, Grant-in-Aid for Exploratory Research of JSPS KAKENHI Grant Number 15K13469.
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