CQS Mini-Symposium

November 18, 2019

Ultrasensitive Graphene Photodetectors - Concepts and Applications

Thanks to a combination of unique electronic, optical, and thermal properties, graphene has emerged as a promising candidate for next-generation optoelectronic sensors. By coupling to photonic structures and employing advanced microwave readout technologies, graphene-based bolometers hold the potential for single-photon detection at infrared, terahertz, and even microwave frequencies, opening up exciting new possibilities in fields ranging from astrophysics to quantum information. This symposium will review the present state of the art in graphene bolometers, the remaining challenges that must be overcome before such detectors can be deployed, and the applications where they might be transformative. 

Far-IR Graphene Bolometer Development at Washington University, Dr. Jordan Russell (Washington University in St. Louis)

Graphene-based Bolometers, Dr. Xu Du (Stony Brook University)

Utilizing graphene as a photon absorber in applications of far-infrared/THz thermal photon detection has received significant research interest in recent years. Graphene has ultra-small volume and low electron density, which gives relatively large heating per absorbed photon, and fast response. At low temperatures the electron-phonon energy loss is small, so ultrasensitive power detection is possible. I will discuss some of the developments in graphene-based bolometers and important issues which need to be considered in making useful real-life detectors, including impedance matching and detector efficiency, electron temperature readout, and thermal isolation of the hot electrons. Addressing these issues I will talk about our work on graphene-superconductor tunnel junction bolometers.

Graphene-based Detectors for Quantum Information and Astrophysics, Dr. Kin Chung Fong (Raytheon BBN Technologies)

The combination of low heat capacity and strong thermal isolation from phonons make the graphene electrons a promising bolometric and calorimetric material. In this talk, we will report our latest experimental progress on (1) achieving a graphene bolometer that reaches the noise equivalent power at the fundamental thermal fluctuation limit and (2) sensing single-infrared-photons using a graphene-based Josephson junction. We will discuss what challenges lie ahead for its applications in superconductor-based quantum information systems, the study of cosmic infrared background, and the search for the QCD dark matter axion.