Three-dimensional terahertz imaging using swept-frequency feedback interferometry with a quantum cascade laser

Opt Lett. 2015 Mar 15;40(6):994-7. doi: 10.1364/OL.40.000994.

Abstract

We demonstrate coherent three-dimensional terahertz imaging by frequency modulation of a quantum cascade laser in a compact and experimentally simple self-mixing scheme. Through this approach, we can realize significantly faster acquisition rates compared to previous schemes employing longitudinal mechanical scanning of a sample. We achieve a depth resolution of better than 0.1 μm with a power noise spectral density below -50 dB/Hz, for a sampling time of 10 ms/pixel.