Anti-Stokes emission in LaAlO3 crystal doped with Tm3+ ions

Abstract LaAlO 3 single crystal doped with Tm 3+ ions was investigated. After continuous wave excitation of the 3 F 2 level (at about 15,115 cm −1 ) strong violet and UV light was observed which corresponds to the 1 D 2  →  3 F 4 (22,000 cm −1 ) and the 1 D 2  →  3 H 6 (27,700 cm −1 ) as well as the 3 P 0  →  3 F 4  (28,600 cm −1 ) transition, respectively. Emission and excitation spectra of the Stokes and anti-Stokes emission were measured. Excitation spectrum was compared with absorption one. Power dependence of the anti-Stokes emission was recorded and analyzed. Possible mechanisms of three or more photons excited state absorption (ESA) and cross-relaxation are discussed.