Dual-wavelength passively mode-locked Nd: GdVO4 laser with orthogonal polarizations

A passively mode-locked dual-wavelength Nd: GdVO4 laser with orthogonal polarizations is experimentally demonstrated. By changing the absorbed pump power, the laser can mode lock either at 1063 nm (with π polarization) or 1065 nm (with σ polarization), or simultaneously at both wavelengths with orthogonal polarizations. When mode locked at 1063 nm and 1065 nm, the laser produced pulses of 10 ps and 5.9 ps, respectively, with repetition rates of 143.7 MHz and 143.9 MHz. When simultaneously mode locked at both wavelengths, the pulsewidth was about 7 ps. The laser was demonstrated by exploiting the thermal lens and birefringence of the Nd: GdVO4 crystal. The laser uses one cavity and does not require the insertion of additional optical components.