Ground-based differential absorption lidar for water-vapor and temperature profiling: development and specifications of a high-performance laser transmitter

摘要

An all-solid-state laser transmitter for a water-vapor and temperature differential absorption lidar (DIAL) system in the near infrared is introduced. The laser system is based on a master-slave configuration. As the slave laser a Q-switched unidirectional alexandrite ring laser is used, which is injection seeded by the master laser, a cw Ti:sapphire ring laser. It is demonstrated that this laser system has, what is to my knowledge, the highest frequency stability (15 MHz rms), narrowest bandwidth (<40 MHz), and highest spectral purity (>99.99%) of all the laser transmitters developed to date in the near infrared. These specifications fulfill the requirements for water-vapor measurements with an error caused by laser properties of <5% and temperature measurements with an error caused by laser properties of <1 K in the whole troposphere. The specifications are maintained during long-term operation in the field. The single-mode operation of this laser system makes the narrow-band detection of the DIAL backscatter signal possible. Thus the system has the potential to be used for accurate temperature measurements and for simultaneous DIAL and Doppler wind measurements. (C) 1998 Optical Society of America. [References: 87]