Frequency stabilization of internal-mirror He-Ne lasers by a flowing-water method

An experiment is conducted to investigate long-term frequency stabilization, with emphasis on plasma tube temperature control by flowing water. The method's features include: (1) flowing water is used to control plasma tube temperature stably and finely; (2) the overall temperature is affected, so that control does not cause thermally-induced distortion of the tube; (3) further stabilization may be attained through suitable modification of the method; and (4) the method may be applicable to the stabilization of high-power laser frequency.