New cavity configurations of Nd:MgO:LiNbO3 self-frequency-doubled lasers

Two types of self-frequency-doubled Nd:MgO:LiNbO3 laser are demonstrated. Their oscillation polarization directions were controlled for second harmonic generation with new cavity configurations which are smaller than the conventional cavity configuration containing a Brewster window. The first laser uses an etalon effect to select the oscillation polarization direction. It emits 0.27 mW of green light (0.546 μm) from a single side of the cavity in quasi CW mode when the crystal absorbs 33 mW of pump light (0.813 μm) from a laser diode. The second laser has a monolithic cavity and the polarization selection is achieved with angle-walk-off caused by birefringence. It emits about 0.2 mW of green light in quasi CW mode when about 100 mW of pump light is incident. In addition to these experiments, the effectiveness of these polarization selection methods is numerically confirmed.