Design, Analysis and Testing of a Wavelength-Agile DIAL System for Long-Standoff Range Operation

The U.S. Air Force Phillips Laboratory is developing a differential absorption light detection and ranging (DIAL) system for use in long range remote sensing of trace atmospheric species. A wavelength-agile (WAL) transverse-electric-atmospheric (TEA) CO2 laser operating on P-and R-branch transitions in the 9.4 pm and 10.4 pin bands is used as the pulsed radiation source for the system. A master oscillator-power amplifier (MOPA) WAL configuration is planned for the future to achieve the necessary increase in pulse energy required for extended range operation. The key system components, including the WAL source and power amplifier, transmitter and receiver optical systems, and data collection equipment are described. The results of preliminary tests using an SF6 absorption cell in a 50 m laboratory path and field measurements using a 3.2 km path at the Phillips Laboratory Starfire Optical Range (SOR) are presented. Performance predictions for operation using the WAL source alone and for the MOPA configuration for extended ranges are presented and discussed.