Control of laser light with nonlinear polarization mirrors

Nikola Ivanov Nikolov

Department of Informatics and Mathematical Modelling,
Building 321, Technical University of Denmark,
2800 Kongens Lyngby, Denmark

I. Buchvarov

University of Sofia, Quantum Electronics Department
5 J. Bouchier Blvd., 1164 Sofia, Bulgaria

Abstract: A new method using frequency doubling polarisation mirror (FDPM), for passive mode-locking and Q-switching of high power lasers have been proposed. The new technique is based on the intensity dependent reflection of the FDPM, which is due to the polarisation rotation of the fundamental wave in a nonlinear crystal for second type (type II) second harmonic generation (SHG). The dependence of the properties of the FDPM on the nonlinear charecteristics and the otientation of the nonlinear crystal, as well as on the accumulated phase shift between the second harmonic and the fundamental wave within the space between the nonlinear crystal and the back reflector were investigated. Dynamics of the generation evolution in laser with FDPM, using rate equations has been analized. This new method has a very large spectral range, and the lack of absorption losses make it appropriate for passive Q-switching of high evarage power lasers.