A crystalline-orientation self-selected linearly polarized Yb:Y3Al5O12 microchip laser

Crystalline-orientation and pump dependent polarization states of Yb:Y(3)Al(5)O(12) microchip lasers were observed experimentally. Linear polarization was observed at six crystalline orientations in the (111) plane relative to the beam propagation direction along the (111) crystalline axis of Yb:Y(3)Al(5)O(12) crystal. The extinction ratio of the linear polarization decreases and the laser tends to oscillate at random polarization state at high pump power levels. Linear polarization states of Yb:Y(3)Al(5)O(12) microchip laser was selected by the anisotropic spectroscopic properties of the Yb(3+)-ion in cubic Y(3)Al(5)O(12) crystal. The random polarization oscillation at high pump power was caused by the strong thermal-induced birefringence and depolarization. (c) 2008 American Institute of Physics.