Polarization switching in the 2-µm Tm:KLu(WO4)2 laser

Abstract

We report on polarization switching in the Tm:KLu(WO4)2 laser between the Nm and Np states oscillating at different wavelengths: 1946 nm for Nm and 1922 nm for Np. There is a certain power range where the two laser polarizations coexist in this biaxial crystal. The switching strongly depends on the thermal management of the active medium through either the mode matching between the pump and the laser beams or the cooling of the crystal faces.