Pattern formation in optical parametric oscillators - art. no. 023803

We have observed transverse pattern formation in type-H continuous-wave tri ply resonant optical parametric oscillators (OPOs). Different kinds of cavi ties with degenerate transverse modes have been studied: confocal, concentr ic, semiconcentric, and planar. We have investigated the OPO oscillation th reshold and the transverse intensity distribution of the emitted fields as a function of the distance from the degeneracy position. The experimental c onfigurations for which the system is truly multimode have been determined.