Frequency stabilization of a radio frequency excited CO 2 laser using the photoacoustic effect

A frequency and a power of rf excited CO 2 laser are stabilized using the photoacoustic effect generated from the laser itself. As the radiation intensity in a laser resonator changed, the pressure of laser medium gas changed due to its photoacoustic effect. A condenser microphone built in the resonator is used to convert delicate variations in the pressure into voltage signals to be used as input signals for lock-in stabilizer. As a result of stabilizing the frequency and power of the laser oscillated from P ( 20 ) line, at the apex of gain curve, the relative stability of the optical frequency and the rate of change in laser power are 5.57 × 10 − 8 and 9.3%, respectively.