Effect of the vibration-translation transfer rate on laser-induced frequency chirp in a long-pulse CO2 laser

Abstract

A frequency sweeping (chirping) mechanism governed by the lasing gas pressure and composition has been observed in a long-pulse TE CO2 laser for the first time. The mechanism was detected in heterodyned data obtained from photomixing the pulsed laser output with a cw local oscillator. A theory has been developed which links this chirp-governing mechanism to the vibration-translation (V-T) transfer rate from the lower laser level to the ground state. This new theory extends the existing theories on chirp in pulsed CO2 lasers into the long-pulse regime.

Observation of intra-pulse thermal effect induced double pulsing in a single-mode TEA CO2laser

“…The heat deposited into the gas due to vibrational-translational (V-T) relaxation during lasing is known to result in intra-pulse frequency chirp in the operation of a pulsed CO 2 laser [1][2][3]. We report here that this effect can also lead to the emission of two pulses from a single-mode CO 2 laser when operated under detuned conditions.…”