Large area photodetector based on microwave cavity perturbation techniques

Abstract

We present a preliminary study to develop a large area photodetector, based on a semiconductor crystal placed inside a superconducting resonant cavity. Laser pulses are detected through a variation of the cavity impedance, as a consequence of the conductivity change in the semiconductor. A novel method, whereby the designed photodetector is simulated by finite element analysis, makes it possible to perform pulse-height spectroscopy on the reflected microwave signals. We measure an energy sensitivity of 100 fJ in the average mode without the employment of low noise electronics and suggest possible ways to further reduce the single-shot detection threshold, based on the results of the described method.

Ultrafast sensing of photoconductivity decay using microwave resonators

“…In addition, both frequency and Q-factor changes lead to a modified reflection, thus modeling to obtain material dependent parameters is rather involved 18,23,24 . Nevertheless, the approach yields effective µ-PCD lifetime values and it was successful in constructing sensitive electromagnetic radiation detectors 21,[25][26][27] .…”