Regenerative Terahertz Quantum Detectors

TL;DR

This paper demonstrates that quantum cascade lasers can be used as highly sensitive, tunable terahertz detectors with high bandwidth, capable of detecting optical beatnotes from THz frequency combs, operating effectively up to 80K.

Contribution

It introduces a novel application of quantum cascade lasers as resonantly amplified terahertz detectors with high responsivity and bandwidth, suitable for frequency comb detection.

Findings

Responsivities up to 50 V/W at 4.7 THz

Noise equivalent power down to 100 pW/√Hz

Electrical bandwidths exceeding 20 GHz

Abstract

Because of the ultrafast and photon-driven nature of the transport in their active region, we demonstrate that quantum cascade lasers can be operated as resonantly amplified terahertz detectors. Tunable responsivities up to 50 V/W and noise equivalent powers down to 100 pW/sqrt(Hz) are demonstrated at 4.7 THz. Constant peak responsivities with respect to the detector temperature are observed up to 80K. Thanks to the sub-ps intersubband lifetime electrical bandwidths larger than 20 GHz can be obtained, allowing the detection of optical beatnotes from quantum cascade THz frequency combs.