Abstract-Multi-spectral terahertz sensing: proposal for a coupled-cavity quantum cascade laser based optical feedback interferometer

Xiaoqiong Qi, Gary Agnew, Iman Kundu, Thomas Taimre, Yah Leng Lim, Karl Bertling, Paul Dean, Andrew Grier, Alexander Valavanis, Edmund H. Linfield, A. Giles Davies, Dragan Indjin, and Aleksandar D. Rakić

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-9-10153

We propose a laser feedback interferometer operating at multiple terahertz (THz) frequency bands by using a pulsed coupled-cavity THz quantum cascade laser (QCL) under optical feedback. A theoretical model that contains multi-mode reduced rate equations and thermal equations is presented, which captures the interplay between electro-optical, thermal, and feedback effects. By using the self-heating effect in both active and passive cavities, self-mixing signal responses at three different THz frequency bands are predicted. A multi-spectral laser feedback interferometry system based on such a coupled-cavity THz QCL will permit ultra-high-speed sensing and spectroscopic applications including material identification.

Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.