Pulsed OPO brightness improvement by means of intracavity spatial filtering
Résumé
The design and operation of a pulsed optical parametric oscillator (OPO) with an intracavity spatial filter is described. This filter, designed to select a single high-order transverse mode, improves the brightness of the generated parametric waves by decreasing their divergence. This process is confirmed by experiments carried out on a KTP OPO pumped at 532 nm, operating close to degeneracy in a singly resonant regime. Comparison of the output energy and beam quality for the OPO with and without intracavity filtering demonstrated a five-fold increase in brightness.