LINE NARROWING AND FREQUENCY STABILIZATION OF HIGH-PRESSURE CO2-LASER BY MEANS OF INJECTION LOCKING WITH MULTI-ISOTOPE MASTER OSCILLATOR

By seeding radiation from a multi-isotope CO2 master oscillator, single-longitudinal-mode operation of a high-pressure CO2 laser with conventional isotopes was realized even at the valley of its gain spectrum between adjacent lines. Spectral characteristics were investigated by the heterodyne detection technique and the frequency up-shift and the subsequent down-chirp were identified as a result of transient refractive index change caused by electron density decay during the build-up of laser pulses. The system was coupled with an electronic feedback loop, and attained the frequency stability of less than +/-5 MHz.