Active phase-nulling of the self-mixing phase in a terahertz frequency quantum cascade laser

作者：Dean P^*; Keeley J; Valavanis A; Bertling K; Lim Y L; Taimre T; Alhathlool R; Li L H; Indjin D; Rakic A D; Linfield E H; Davies A G

来源：Optics Letters, 2015, 40(6): 950-953.

DOI：10.1364/OL.40.000950

We demonstrate an active phase-nulling scheme for terahertz (THz) frequency quantum cascade lasers (QCLs) under optical feedback, by active electronic feedback control of the emission frequency. Using this scheme, the frequency tuning rate of a THz QCL is characterized, with significantly reduced experimental complexity compared to alternative approaches. Furthermore, we demonstrate real-time displacement sensing of targets, overcoming the resolution limits imposed by quantization in previously implemented fringe-counting methods. Our approach is readily applicable to high-frequency vibrometry and surface profiling of targets, as well as frequency-stabilization schemes for THz QCLs.

• 出版日期2015-3-15