Using coherence properties for frequency stabilizing He-Ne laser

Abstract

We have demonstrated that the frequency of the laser radiation can be stabilized by controlling its coherence properties. Theoretical analysis of the laser radiation visibility function was performed and connection with the longitudinal mode structure was established. It was established that laser emission frequency could be stabilized by controlling the visibility of interference pattern,. Calculations have shown that, in theory, stability around 4 kHz can be expected. As a proof-of-the-principle, a HeNe laser, stabilized by measurement of the interference pattern visibility in a modified Michelson interferometer, was built. Stabilization was performed by temperature control of the laser tube in a digital feedback ioop and total frequency variation of 3 MHz was obtained. Possible improvements of the experimental setup, together with some applications ofmultimode stabilized lasers are discussed.