Spectrophone stabilization and offset tuning of a carbon dioxide waveguide laser

A sensitive spectrophone containing CO
2
gas is incorporated into a feedback loop to stabilize the frequency of a CO
2
waveguide laser. First or second harmonic detection combined with a zero offset feature and the relatively high operating pressure of the laser allows continuous tuning of the stabilized frequency over a 400 MHz range. Frequency stability of better than ±1 MHz is achieved.