Prospects of monoclinic Yb:KLu(WO4)2 crystal for multi-watt microchip lasers

Identifier:  PC:1160

Handle: https://hdl.handle.net/20.500.11797/PC1160

Authors:  Francesc Díaz; Magdalena Aguiló; Uwe Griebner; Valentin Petrov; Nikolai Kuleshov; Konstantin Yumashev; Pavel Loiko; Josep Maria Serres; Xavier Mateos

Abstract:
Abstract: The concept of Yb-doped double tungstate microchip lasers is verified and scaled to the multi-watt power level. The active element is a 2.6 mm-thick Yb:KLuW crystal cut along the Ng optical indicatrix axis. Maximum continuous-wave output power of 4.4 W is extracted at 1049 nm with a slope efficiency of 65% and an optical-to-optical efficiency of 44% with respect to the absorbed pump power. The laser emission is linearly polarized and the intensity profile is characterized by a near-circular TEM00 mode with M2 x,y < 1.1. Due to low intracavity losses of the microchip laser, laser operation at wavelengths as long as 1063 nm is achieved. The mechanism of the thermal mode stabilization in the microchip cavity is confirmed. At very low resonator losses polarization-switching between E || Nm and Np oscillating states is observed and explained on the basis of spectroscopic and thermal lens characteristics.