Operating Temperature Dependence of QDOGFET Single-Photon Detectors

Abstract

Abstract:We report on the temperature dependence of the photosensitivity of a quantum dot, optically gated, field-effect transistor (QDOGFET) that uses self-assembled semiconductor quantum dots embedded in a high-electron-mobility transistor to detect individual photons of light. Paramount to the operation of the device is differentiating weak, photo-induced signals from random fluctuations associated with electrical noise. To date, QDOGFETs have only been shown to be single-photon sensitive when cooled to 4 K. Here, we study noise spectra of a QDOGFET for sample temperatures ranging from 7-60 K and discuss how the noise affects the sensitivity of the device when operated at elevated temperatures. We show that the QDOGFET maintains single-photon sensitivity for temperatures up to 35-40 K where increases in operating temperature can be traded for decreases in signal-to-noise ratio. IntroductionSingle-photon detector (SPD) development is crucial to the advancement of quantum information technologies and measurement science. More effective SPDs are needed to improve the security of quantum communication systems based on quantum-key distribution (Hiskett et al., 2006) and to extend the link lengths and data rates of deep-space communications (Mendenhall et al., 2007;Hemmati et al., 2007;Boroson et al., 2004). SPDs are fundamental tools for quantum optics experiments and also impact the areas of observational astronomy, medical diagnosis and imaging, and light detection and ranging (LIDAR) (Priedhorsky et al., 1996). In general, desirable characteristics for SPDs include high detection rates, low dark counts, and high detection efficiency. Some applications require detectors that are not only sensitive to single photons, but that can also count the number of incident photons that arrive simultaneously. Photon-number resolution is critical for the realization of linear optics quantum computing (Knill et al., 2001), impacts the security of quantum communications (Brassard et al., 2000), and is useful for studying the quantum nature of light (Giuseppe et al., 2003;Waks et al., 2004;Achilles et al., 2006;Waks et al., 2006). In addition, for many commercial applications, SPDs must be compact and exhibit modest power and cooling requirement for operation.