Frequency and power stabilization of radio frequency excited CO 2 laser using photoacoustic effect

We stabilized the frequency and power of a CW radio-frequency-excited laser on the peak of the Doppler broadened gain curve using the photoacoustic effect generated from the laser itself. The condenser microphone is installed in the radio frequency discharge chamber to detect a photoacoustic signal. The photoacoustic signal is fed to a lock-in stabilizer as a reference signal for stabilization. The frequency stability is estimated to be better then 5.410 at the P(20) line. The stabilized output variation was reduced 9.3%, compared to 100% for a free running laser.