A new stabilization system for optically pumped cw far infrared lasers

A new type of stabilization system for optically pumped far infrared (FIR) lasers based on a dual modulation technique is described, which enables to control the laser output power both as a function of the CO₂-laser pumping frequency and the FIR laser cavity length. The system greatly improves the laser output stability and causes only a negligible modulation (<1 %) of the output power. An additional feature, an electronic search circuit for emission lines, simplifies working at the laser even by ineperienced people.