Control of laser light power output for use in light scattering instruments by inducing mode hopping and averaging result

摘要

The incorporation of certain classes of solid state lasers into light scattering instrumentation is desirable because of their compact structure. However, mode hopping often causes the output power produced by such lasers to be unstable. The frequency of such output power fluctuations is often so broad that output power monitoring means, characteristic of the light scattering instrumentation into which such lasers are incorporated, cannot track accurately the temporal output power fluctuations. A method, and associated apparatus, is described whereby the laser drive current is modulated at low frequency and amplitude sufficient to induce and thereby control mode hopping so as to permit accurate measurement of the ratio of light scattering signals to the laser output power.