Laser Performance and Temperature-Dependent Spectroscopy of Titanium-Doped Crystals

Abstract

Ti:sapphire (Ti³⁺:Al₂O₃) is of strong interest because of its ability to lase over a continuobsTy tunable, broadband, spectral region [1]. However, crystal quality has continued to be plagued by problems with the presence of scattering centers and spurious absorption losses in the spectral region where lasing is expected. To assess the current state-of-the-art in Ti:sapphire crystal growth, laser crystals were procured from two crystal growth facilities. A crystal 48 mm long by 5 mm in diameter with Brewster angle ends was cut from a boule grown by the Czochralski (CZ) method. It had a nominal doping of 0.1 wt% titanium. Another crystal, 35 mm long and 7 mm in diameter, was grown using the Heat Exchanger Method (HEM); it also had Brewster angle ends. Based on relative absorption of 532 nm laser radiation in the two crystals, the titanium doping level in the HEM crystal was calculated to be 0.03 wt%.