A theoretical analysis of the gain profiles for the two counterpropagating waves that can be simultaneously generated in an optically-pumped ring-cavity FIR laser is performed. Coherent and incoherent nonlinear phenomena involving the travelling pump wave and the two generated waves appear, which give rise to a new kind of directional anisotropy, that can be larger than the well known one based on the different velocity averaging of the Raman two-photon process with forward and backward generated waves. The new anisotropy allows stationary bi-directional emission. A phase diagram showing the uni- and bi-directional regimes has been traced. © 1989.
|Publication status||Published - 15 Feb 1989|