Inter-transverse-mode injection locking and subthreshold gain measurements in a CO/sub 2/ waveguide laser

A higher order CO/sub 2/ waveguide laser resonator mode has been studied both above and below threshold, by reinjecting a frequency shifted portion of the laser output back into the resonator. The relative reinjected (autodyne) gain profile in the vicinity of the subthreshold transverse mode is shown to shift in frequency, reduce in spectral width, and increase in magnitude as the subthreshold mode is brought nearer to threshold by tilting one of the resonator mirrors. Once above threshold, inter-transverse-mode injection locking has been demonstrated, and close to the locking-point higher order terms from the nonlinear interaction are clearly evident.<
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