Incompatibility of cavity resonances with wave-vector matching: influence on threshold and beam structures of optical parametric oscillators

摘要

We investigate theoretically and experimentally the interplay between cavity and double refraction in continuous-wave optical parametric oscillators. We show that basic geometrical effects can prevent transverse wave-vector matching for TEM00 modes and thus increase the threshold and dramatically change the beam structures when a resonant (or double-pass) pump is used. We extend the results of Boyd and Kleinman [J. Appl. Phys, 39, 3597 (1968)] to take these cavity-induced mismatches into account and test the theoretical results experimentally, using a continuous-wave type II KTP optical parametric oscillator. The transverse wave-vector mismatch leads to the appearance of transverse modes with increasing order (up to TEM40 (0))The theory is able to predict quantitatively all selected transverse modes and admits of a simple interpretation in transverse Fourier space. (C) 2002 Optical Society of America. [References: 23]