9423883 Prasad This Small Business Innovation Research (SBIR) Phase II project will develop a 0.5 watt, diode-pumped lithium sulfur argon fluorine (LiSAF) laser, tunable continuously from 780 to 1000 nanometers, with a single longitudinal mode (SLM), high spectral purity output. The innovation in the laser system is a three-mirror ring traveling wave main laser cavity, coupled to an external ring cavity etalon containing a birefringent tuner (BRT) for self-injection locking. In Phase I an analytical simulation of the system found that for an optimal choice of cavity parameters excellent discrimination (>104) is achieved with high spectral purity, SLM operation, and BRT tuning. Phase I experiments with a diode-pumped Cr3+ :LiSAF laser yielded high slope efficiency, corresponding to an intrinsic efficiency (54%) close to the theoretical limit. Phase II research will focus on cavity coupling parameters, self injection locking, cavity length control, and wavelength stabilization. Measurements of laser linewidth and spectral purity will be made. A broadly tunable, single-mode laser has many potential applications in high resolution spectroscopy, as an injection seeder for high power lasers, as a laser source for lidars used in environmental monitoring and atmospheric measurements, and in surgical and diagnostic medical tools. LiSAF lasers are expected to be produced at low cost
