Patent ID: 7248397

Claim:
A wavelength-doubling optical parametric oscillator device, comprising: a nonlinear optical medium oriented on an optical path in an optical cavity, a first wave and a second wave being generated within the nonlinear optical medium by a pump beam, the first wave and the second wave each having a wavelength of two times a pump beam wavelength; a first mirror pair comprising an output coupler mirror and a second mirror, the output coupler mirror being an output coupler for the first wave and being positioned to receive the second wave at near Brewster's angle and to reflect the second wave to the second mirror, the second mirror being positioned to reflect the second wave at near Brewster's angle and to reflect the second wave to a third mirror, the third mirror positioned to reflect the second wave to a fourth mirror; the fourth mirror positioned to reflect the second wave to a fifth mirror, wherein a rotation of a polarization of the second wave through 90 degrees is caused by a combined reflection from the third mirror and the fourth mirror; and a second mirror pair comprising the fifth mirror and an input coupler mirror, the fifth mirror being positioned to receive the second wave at near Brewster's angle and to reflect the second wave to the input coupler mirror and the input coupler mirror being positioned to reflect the second wave at near Brewster's angle to the output coupler mirror, wherein an intra-cavity retardation optic is not a component of the optical cavity.