Spectral narrowing in high-gain lasers

The dependence of spectral narrowing in lasers on the line-broadening mechanism is investigated including the effects of saturation and distributed loss. It is found that in the unsaturated regime the narrowing is essentially independent of the resonance broadening mechanism and the narrowed line approaches a Gaussian. The onset of saturation slows or reverses the narrowing process. Experimental results have been obtained using a 3.51-μ xenon laser.