Optical and Mass Spectroscopic Analyses of Titanium-Doped Sapphire Crystals

Abstract

Remote sensing of atmospheric species from space-based platforms using differential absorption LIDAR (DIAL) will require a high -energy, long lifetime, efficient, and tunable laser transmitter. Tunable solid state laser materials such as titanium-doped sapphire (Ti:Sapphire) and alexandrite are currently candidates for DIAL laser transmitters. The interest in the development of laser quality Ti:Sapphire is based on its broad tuning range which extends into the near IR (700 to 1100 nm) MOULTON [1]. However, initial growths of Ti:Sapphire exhibited significant and deleterious absorption in the lasing region as shown in Figure 1. One of the hypotheses suggested for the origin of this parasitic absorption is the presence of impurities incorporated into the laser crystal at growth. Evidence for the presence of such an impurity ion appears in the fluorescence spectrum of Ti:Sapphire excited by 514.5 nm radiation from an argon ion laser (Figure 2). The sharp peak at 690 nm is attributed to the R-lines of chromium.