Thermal lens investigation in EuF<inf>2.11</inf>, PrF<inf>3</inf>, and Na<inf>0.38</inf>Ho<inf>0.62</inf>F<inf>2.24</inf> crystals for magnetooptical applications

Abstract

© 2019 Elsevier B.V. Thermal lens, absorption coefficient for 1076 nm radiation and spectral dependence of the Verdet constant were measured in PrF3, EuF2.11 and Na0.38Ho0.62F2.24 crystals for magneto-optical applications. As evaluated in the 400–1310 nm wavelength range, the Verdet constant of the EuF2.11 crystals is ~30% higher than that of the TGG crystals, an at the wavelength of 1557 nm it is 100% higher. The Verdet constant of PrF3 crystals is ~5% lower than in TGG throughout the studied wavelength range. Na0.38Ho0.62F2.24 crystals have the lowest (among the studied crystals) value of the Verdet constant that is 50–80% lower than in TGG. The thermal lens was measured by the phase-shift interferometry technique and has the sign opposite to that of the TGG lens for all considered crystal. The thermo-optical constant P and the dependence of the thermal lens on the absorbed power were calculated. It is shown that the optical power of thermal lens in PrF3, EuF2.11 and Na0.38Ho0.62F2.24 at equal absorbed laser power is, respectively, 1.3, 1.7 and 1.8 times higher than in TGG.