Frequency Chirp of a Low-Pressure Hybrid TE CO2 Laser.

摘要

The frequency chirp in the output of a hybrid TE CO2 laser has been measured using a heterodyne technique. Due to the low operating pressure of about 35 Torr, laser kinetic and hydrodynamic processes differ considerably in time scale from those in regular TEA CO2 lasers. The chirps in laser pulses up to 150 microsec long could not be described adequately with existing theories. Almost complete cancellation of the laser chirp was achieved by appropriate use of acousto-optic modulators external to the hybrid TE CO2 laser. The operating and output characteristics of this laser and other parameters related to chirp will be discussed. Keywords: Frequency chirp; Acoustic optic modulators; Chirp cancellation; Reprints. (jhd)