We present an experimental observation of the output responses of a Nd:YAG microchip laser with an anisotropic external cavity under weak optical feedback. The feedback mirror is stationary during the experiments. A pair of acousto-optic modulators is used to produce a frequency shift in the feedback light with respect to the initial light. The laser output is a beat signal with 40 kHz modulation frequency and is separated into two orthogonal directions by a Wollaston prism. Phase differences between the two intensity curves are observed as the laser works in two orthogonal modes, and vary with the external birefringence element and the pump power. Theoretical analyses are given, and the simulated results are consistent with the experimental phenomena.
© 2013 Optical Society of America
Lasers and Laser Optics
Original Manuscript: August 2, 2013
Revised Manuscript: September 17, 2013
Manuscript Accepted: September 23, 2013
Published: October 18, 2013
Peng Zhang, Yi-Dong Tan, Ning Liu, Yun Wu, and Shu-Lian Zhang, "Phase difference in modulated signals of two orthogonally polarized outputs of a Nd:YAG microchip laser with anisotropic optical feedback," Opt. Lett. 38, 4296-4299 (2013)