Laser performance of LiSrAlF6:Cr3+

Abstract

We have lased the new material, LiSrAlF₆:Cr³⁺ (Cr³⁺:LiSAF). The single crystals were grown by the horizontal zone melting technique. The spectroscopic properties of Cr³⁺:LiSAF are similar to those of other low‐field Cr³⁺‐doped systems, although the emission cross section is strongly π polarized and is also somewhat larger than has been measured for other fluoride hosts. The free‐running lasing wavelength of Cr³⁺:LiSAF is 825 nm, and the tuning range extends from at least 780 to 920 nm. Using Kr laser pumping, we obtained slope efficiencies of 36% and 14% by utilizing output couplings of 4.8% and 0.8%, respectively. On the basis of these results, the extrapolated maximum efficiency of 53% is determined, to be compared to the quantum defect‐limited value of 78%. It is concluded that a moderate level of excited state absorption (ESA) loss is responsible for the reduced efficiency of the Cr³⁺:LiSAF system. This contrasts with the related results previously obtained for LiCaAlF₆:Cr³⁺, where it was concluded that the effects of ESA were negligible [IEEE J. Quantum Electron. Q E ‐ 2 4, 2243 (1988)].