title: Polarization anisotropy of thermal lens in Yb:KY(WO4)2laser crystal under high-power diode pumping.
abstract: Thermal lensing was studied in an Ng-cut monoclinic Yb:KY(WO4)2(Yb:KYW) laser crystal under high-power diode pumping at ∼980  nm, for the two principal light polarizations, E||Nmand E||Np. For both polarizations, the thermal lens (TL) was positive. It was found that operation of an Yb:KYW laser with the E||Nppolarization corresponds to a weaker TL that results in a better quality of the laser beam and superior power scaling capabilities. The sensitivity factors of the TL in this case were M=0.37 and 0.57  m-1/W for the mg and pg principal meridional planes, respectively, and the astigmatism degree was as low as S/M=35% (for a pump beam radius of wp=175  μm). The photoelastic terms, fractional heat loading, and generalized thermo-optic coefficients were evaluated.
authors.forename: Pavel
authors.initials: P
authors.lastname: Loiko
authors.forename: Sujith
authors.initials: S
authors.lastname: Manjooran
authors.forename: Konstantin
authors.initials: K
authors.lastname: Yumashev
authors.forename: Arkady
authors.initials: A
authors.lastname: Major