Abstract

Cr-doped garnet lasers exhibit a quite narrow tuning range. To understand this behavior the excited state absorption (ESA) of Cr:GSGG and Cr:LLGG was measured. It is shown that at short wavelengths the tuning curves are limited due to ²E->²T₂ (b), ²T₁ (b) and ⁴T₂-> ⁴T₁(b) ESA transitions, respectively, and by ground-state absorption (GSA). At long wavelengths the ⁴T₂-> ⁴T₁ (a) ESA cuts off the tuning range of both garnets at about 850nm. This is caused by the Jahn-Teller splitting of the excited T-states thus creating an additional high energy ESA band, which overlaps the gain spectrum considerably. The consequence is, that no broader tuning range can be expected in all laser materials with high symmetric Cr-sites.

© 1990 Optical Society of America