Theory of line narrowing and frequency selection in an injection locked laser

We apply the multimode semiclassical laser theory to the problem of line narrowing and frequency selection in an injection locked laser. Our goal is to predict from the spectroscopic properties of a given active medium, the behavior of a broad-band laser that is under the influence of a narrow-band injected signal. Analytic expressions for the injected signal strength necessary for single-mode operation are obtained for both homogeneously and inhomogeneously broadened lasers, and for small-signal and strong-signal regimes. We found that under certain experimental conditions, an injection locked inhomogeneously broadened laser behaves significantly different from a homogeneously broadened lasel.