Abstract

Tunable long wave infrared (LWIR) coherent sources emitting between 8 and 12 µm can be used for versatile remote gas sensing. In ref [1] we implemented a parametric oscillator in which wavelength tunability was achieved by temperature tuning of the crystal indices of refraction. It is well known that a similar wavelength range can be addressed by tuning the pump wavelength rather than the crystal temperature [2]. In addition, pump tuning can be significantly faster than temperature tuning. In this context we also need a narrow band spectrum to control the spectral output of the optical parametric oscillator, which is based on Vernier spectral filtering in doubly-resonant cavities. Seger and his team exhibited single longitudinal mode operation in a microlaser tuned with transversally chirped volume Bragg grating (TC-VBG) near 1 µm [3]. We show how this concept can be applied to a different laser emitting at 2 µm.

© 2019 IEEE