Spectral Holeburning in Titanium-Doped Sapphire and YAG

Abstract

Spectral holeburning in the zero-phonon lines of Al₂O₃:Ti³⁺ (6165Å) and YAG:Ti³⁺ (6502Å) is reported. In Al₂O₃:Ti³⁺, the holes are predominantly transient due to two-level saturation but a shallow persistent hole can be produced which is attributed to photoionization of Ti³⁺. Substantial hole narrowing was observed in external magnetic fields up to 22 kG. In YAG:Ti³⁺, persistent holes 90 MHz wide were readily observed and the holeburning was shown to be linear in laser power, i.e., a one-photon process. The observation that hole burning is essentially non-permanent in Al₂O₃:Ti³⁺ and permanent in YAG:Ti³⁺ suggests that the photostability of Ti³⁺ ions depends strongly on the host crystal.