Injection locking of excimer lasers

The channeling of the energy of high-power excimer lasers into very narrow spectral bandwidths in low divergence beams is a prerequisite for many potential applications of these lasers. High spectral brightness is required for spectroscopic applications and optical harmonic generation, and the long coherence length associated with a narrow bandwidth is required for nonlinear phase conjugation, and backward stimulated Brillouin and Raman scattering among other applications. The simplest way to control the spectral bandwidth and beam divergence of high-gain excimer lasers involves the combined implementation of an unstable resonator and injection locking. The present investigation is concerned with the criteria which determine reliable injection locking of unstable resonator excimer lasers (or other high-gain lasers) with minimal injected power. It is found that the implementation of relatively simple techniques can allow the experimenter with a modest budget and level of effort, to obtain an ultraviolet excimer source of very high quality.