Spectral and spatial limiting in an idler-resonant PPKTP optical parametric oscillator

The spectral and spatial properties of a non-collinear signal- and idler-resonant periodically poled KTiOPO4 optical parametric oscillator (OPO) have been investigated. The lower angular dispersion of the idler-resonant OPO allows for generation of up to two-times smaller spectral bandwidths at large non-collinear angles, and at the same time the beam quality improves considerably compared with the signal-resonant case. The overall efficiency reached 67% in both cases.