Tunable CO2 laser system with subnanosecond-pulse-train output

Abstract

A CO2 laser system has been demonstrated that generates a train of subnanosecond pulses tunable over the P and R branches of the CO2 laser spectrum at 9–11µm. It utilizes optical free induction decay to generate a single ~100-ps laser pulse from a tunable transverse-excited-atmospheric CO2 laser. This laser pulse is injection-seeded into a high-pressure CO2 oscillator whose output consists of a train of amplified ~100-ps pulses with maximum pulse energy of 30mJ, corresponding to a peak power of 300MW. The ~100-ps, tunable, infrared laser pulses are needed for a new technique to remotely detect atmospheric gaseous molecules, which relies on the train of CO2 laser pulses selectively exciting the target molecules whose presence is then revealed using a separate terahertz probe beam.