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Observation of optical feedback dynamics in single-mode terahertz quantum cascade lasers: Transient instabilities

Authors :
Xiaoqiong Qi
Karl Bertling
Ashley Robinson
Thomas Taimre
Gary Agnew
Edmund H. Linfield
Paul Dean
Lianhe Li
Tim Gillespie
Aleksandar Demić
A. Giles Davies
Michael Brünig
Yah Leng Lim
Aleksandar D. Rakić
Dragan Indjin
Publication Year :
2021
Publisher :
American Physical Society, 2021.

Abstract

We provide an experimental evidence of transient instabilities (TIs) in a terahertz (THz) quantum cascade laser (QCL) under optical feedback, in contrast to the widely accepted claim that THz QCLs are ultrastable against feedback. The TIs appear as periodic oscillations in emitted power or terminal voltage of the laser with an increasing oscillation frequency as feedback increases. The absence of relaxation oscillations and low linewidth enhancement factor in THz QCLs makes them a platform uniquely suitable for exploring external-cavity-related dynamics in semiconductor lasers. This work opens a pathway to a THz sensing and imaging modality based on these TIs, which has much reduced complexity compared to existing approaches using laser feedback interferometry.

Details

Language :
English
ISSN :
10502947
Database :
OpenAIRE
Accession number :
edsair.doi.dedup.....c3130cb6d1f268b8de8add40dc2c138c