Internal upconversion and doubling of an optical parametric oscillator to extend the tuning range

Efficient extension of the tuning range of a
1.09-1.95\mu
parametric oscillator to
0.435-0.975\mu
by upconversion and doubling internally to the oscillator cavity is reported. Unlike previously studied external mixing, internal upconversion and doubling yielded uniform powers of 30 and 60 kW, respectively, over the entire extended tuning range with an unfocused 2-mm ruby laser pump beam of 750 kW.