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Single-charge Circuits

Working Group 2.42

Single-photon detection and spectrometry using S-I-N-I-S electron trap

Recently our group demonstrated [1] that a structure similar to the hybrid S-I-N-I-S turnstile but with one terminal open and coupled capacitively to one or several single-electron electrometers (so-called, electron trap, see Figure1) can be implemented as a single-photon detector [2]. The advantage of the trapping device is its extremely high sensitivity down to rare single photons propagating either along the leads or in the space around the detector sample. Due to a simple tunability of the Coulomb blockade threshold in the S-I-N-I-S double junction, the energy discrimination threshold can be adjusted making possible spectral analysis of the incoming photons. The detector can find its application for characterizing the residual radiation spectrum inside mK-environments for metrology and quantum information processing.



Figure 1:
SEM Image of a S-I-N-I-S trap with two coupled electrometers. In the presented experiment [2], the electrometer SET B played the role of a photon emitting device and the electrometer SET A registered the photon-induced charge state switching of the trap.


Figure 2:
Simultaneous signals from two electrometers SET A and SET B shown in Fig.1. A jump between the bottom and the top signal levels within the red curve corresponds to retrapping of exactly one electron. This recharging is induced through absorption of single photons emitted by SET B.



[1] S. V. Lotkhov, O.-P-Saira, J. P. Pekola, and A. B. Zorin, Single-charge escape processes through a hybrid turnstile in a dissipative environment, New J. Phys. 13, 013040 (2011).


[2] S. V. Lotkhov and A. B. Zorin, A hybrid superconductor-normal metal electron trap as a photon detector, Appl. Phys. Lett. 100, 242601 (2012).