Detection of nanosecond-scale, high power THz pulses with a field effect transistor

S Preu; H Lu; M S Sherwin; A C Gossard

doi:10.1063/1.4705986

Detection of nanosecond-scale, high power THz pulses with a field effect transistor

Rev Sci Instrum. 2012 May;83(5):053101. doi: 10.1063/1.4705986.

Authors

S Preu¹, H Lu, M S Sherwin, A C Gossard

Affiliation

¹ Physics Department and Institute for Terahertz Science and Technology, University of California, Santa Barbara, California 93106, USA.

PMID: 22667596
DOI: 10.1063/1.4705986

Abstract

We demonstrate detection and resolution of high power, 34 ns free electron laser pulses using a rectifying field effect transistor. The detector remains linear up to an input power of 11 ± 0.5 W at a pulse energy of 20 ± 1 μJ at 240 GHz. We compare its performance to a protected Schottky diode, finding a shorter intrinsic time constant. The damage threshold is estimated to be a few 100 W. The detector is, therefore, well-suited for characterizing high power THz pulses. We further demonstrate that the same detector can be used to detect low power continuous-wave THz signals with a post detection limited noise floor of 3.1 μW/√Hz. Such ultrafast, high power detectors are important tools for high power and high energy THz facilities such as free electron lasers.