Graphene-Based Calorimetric Single-Photon Detection

High-sensitivity detectors for electromagnetic waves are essential in wide ranges of applications, such as astronomy, radar systems, quantum computing, and quantum communication. Depending on the spectrum of interest, detectors based on different material platforms, detection mechanisms, and coupling methods are developed over the years. However, detecting single photons remains a very challenging experiment especially at low frequencies because of the low photon energy. In this talk, we will present how to take advantage of the giant thermal response of graphene electrons for photon detection. Interestingly, when our graphene bolometer achieves a record-high sensitivity of 10-19 W/Hz1/2, this sensitivity is limited, no longer by extrinsic factors but, by the statistical thermal fluctuation intrinsic to the graphene electrons as a canonical ensemble at 0.2 K [1]. Using the graphene-based Josephson junction, we demonstrate the single-photon detection in the infrared regime by observing the photon shot noise [2]. More recently, we are able to demonstrate single-photon detection by sensing the internal energy of individual photons, a new paradigm known as single-photon calorimetry. As an outlook, we will discuss how we can apply this new technologies to a wider electromagnetic spectrum, from near to far infrared, as well as to resolve spatial mode of a single photon [3].<br/>References:<br/>G.-H. Lee, et. al., “Graphene-based Josephson junction microwave bolometer,” Nature 586, 42 (2020).<br/>E. D. Walsh, et. al., “Josephson junction infrared single-photon detector,” Science 372, 409 (2021).<br/>C. Fried, et. al., “6. “Performance limits to graphene single-photon bolometers by thermal transport,” Phys. Rev. Applied 21, 014006 (2024)..