Certain practical difficulties are encountered in positioning a pump source comprising very-small-diameter electroluminescent diodes in direct physical contact with an associated laser rod. These difficulties are surmounted by positioning the diodes and the rod in a spaced-apart relationship and imaging the emitting areas of the diodes to positions slightly within the rod. In addition, a major portion of the surface of the rod is coated with a reflective material whereby radiation that enters the rod is multiply reflected therein. In this way the radiant output of the diodes is coupled to the rod in a highly efficient manner by means of a structure that is easily realized.
展开▼
