Dynamics of optical mixing in a He-Ne laser

The difference frequency between two 3.39-μ signals injected into a 6328-Å and/or 1.15-μ He-Ne laser has been detected as an amplitude modulation of the 6328-Å and/or output intensity. Whereas the presence of 3.39-μ radiation decreased the 6328-Å intensity, it was found to increase the 1.15-μ intensity. Experimental measurements of the bandwidth of this detection scheme have been made for a 6328-Å laser detector. Under typical operating conditions the optimum bandwidth, which occurred for maximum 6328-Å laser intensity, was of the order of 500 kHz. It is shown that the rate-equation approach gives an adequate description of the dynamics of laser response and indicates the operating conditions that are necessary in order to achieve optimum bandwidth.