Dither-free stabilization of CO2 lasers for far infrared pumping: A photoacoustic approach

A method based on the photoacoustic technique is described for dither-free frequency stabilization of the optical pump in a CH
3
OH laser operating at 119 μm. Heterodyne measurements on two independently locked FIR lasers indicate excellent long term frequency and power stability. This stabilization scheme should be applicable to all optically pumped FIR lasants.