Saturation of anomalous dispersion in cw HF lasers

The high gain and narrow linewidth of HF chemical lasers lead to a large resonant component of the refractive index. Calculations indicate that this (unsaturated) anomalous dispersion is at least as large as the non-resonant Gladstone-Dale dispersion. Possible deleterious effects of anomalous dispersion are briefly reviewed. These effects in a high-power device are mitigated by multimode operation, which acts to saturate homogeneously the anomalous dispersion at intensities considerably lower than those required for power broadening of the inhomogeneous Doppler line shape over to a homogeneous line.