Fast detector of the ellipticity of infrared and terahertz radiation based on HgTe quantum well structures

TL;DR

This paper introduces a rapid, room-temperature, all-electric device for measuring the polarization ellipticity of laser radiation across infrared to terahertz frequencies, utilizing photogalvanic effects in semiconductors.

Contribution

The paper presents a novel, fast detection scheme for polarization ellipticity based on photogalvanic effects in HgTe quantum wells and other semiconductors, operational at room temperature.

Findings

Device works across infrared to terahertz range.

Effective with various laser types and powers.

Uses simple, all-electric detection method.

Abstract

We report a fast, room temperature detection scheme for the polarization ellipticity of laser radiation, with a bandwidth that stretches from the infrared to the terahertz range. The device consists of two elements, one in front of the other, that detect the polarization ellipticity and the azimuthal angle of the ellipse. The elements respectively utilise the circular photogalvanic effect in a narrow gap semiconductor and the linear photogalvanic effect in a bulk piezoelectric semiconductor. For the former we characterized both a HgTe quantum well and bulk Te, and for the latter, bulk GaAs. In contrast with optical methods our device is an easy to handle all-electric approach, which we demonstrated by applying a large number of different lasers from low power, continuous wave systems to high power, pulsed sources.