The 77th JSAP Autumn Meeting, 2016

Presentation information

Poster presentation

3 Optics and Photonics » 3.8 Optical measurement, instrumentation, and sensor

[14a-P2-1~13] 3.8 Optical measurement, instrumentation, and sensor

Wed. Sep 14, 2016 9:30 AM - 11:30 AM P2 (Exhibition Hall)

9:30 AM - 11:30 AM

[14a-P2-6] Optical feedback in a distributed feedback quantum cascade laser and linewidth reduction for cavity ring-down spectroscopy

〇(PC)Volker Thomas Sonnenschein1, Ryohei Terabasyashi1, Noriyoshi Hayashi1, Shuusuke Kato1, Hideki Tomita1, Lei Jin1, Masahito Yamanaka1, Norihiko Nishizawa1, Atsushi Sato2, Kohei Nozawa2, Kenta Hashizume2, Toshinari Oh-Hara2, Tetsuo Iguchi1 (1.Nagoya Univ., 2.Sekisui Med. ADME&Tox.)

Keywords:QCL, feedback, linewidth

Maximal transmission through a high finesse optical cavity, such as those used in Cavity Ring-Down Spectroscopy, is only achieved if the linewidth of the exciting laser is at least as narrow as the transmission peak given by the Airy function. For our system a linewidth of less than 50kHz would be required, which is not generally achieved using standard commercial distributed feedback (DFB) or external cavity QCL lasers, which typically feature a linewidth of more than 1MHz.
Optical feedback is known to reduce the short-term linewidth of lasers. We present results based on a simple external feedback mirror, demonstrating the effects on tuning behavior and linewidth narrowing.
Measurements were carried out both using a simple low-finesse Fabry-Perot Inetrferometer as well as by monitoring the output of the CRDS cavity itself.