Amplitude modulation of radiation from waveguide CO2 lasers with transverse rf excitation

An investigation was made of low frequency amplitude modulation of the output radiation from sealed CO₂ lasers with plane–plane resonators, induced by modulating the power of an rf pump source. For rf electrode voltage modulation levels of ~ 14%, the stimulated emission modulation depth in the frequency range 0.8–3 kHz reached 100%. The maximum modulation frequency, at the 0.5 level, was a function of the pressure, the active mixture composition, and the dimensions of the discharge capillary. It was 4–14 kHz for lasers with 2–3 mm diameter waveguides. Acoustic vibrations (waves) appeared at the modulation frequency in the transverse rf discharge plasma. These waves influenced the laser output power.