1 March 2010 Development of a widely tunable amplified diode laser differential absorption lidar for profiling atmospheric water vapor
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J. of Applied Remote Sensing, 4(1), 043515 (2010). doi:10.1117/1.3383156
Abstract
This work describes the design and testing of a highly-tunable differential absorption lidar (DIAL) instrument utilizing an all-semiconductor transmitter. This new DIAL instrument transmitter has a highly-tunable external cavity diode laser (ECDL) as a seed laser source for two cascaded commercial tapered amplifiers. The transmitter has the capability of tuning over a range of ~ 17 nm centered at about 832 nm to selectively probe several water vapor absorption lines. This capability has been requested in other recent DIAL experiments for wavelengths near 830 nm. The transmitter produces pulse energies of approximately 0.25 µJ at a repetition rate of 20 kHz. The linewidth is exceptionally narrow at <0.3 MHz, with frequency stability that has been shown to be +/- 88 MHz and spectral purity of 0.995. Tests of the DIAL instrument to prove the validity of its measurements were undertaken. Preliminary water vapor profiles, taken in Bozeman, Montana, agree to within 5-60% with profiles derived from co-located radiosondes 800 meters above ground altitude. Below 800 meters, the measurements are biased low due to a number of systematic issues that are discussed. The long averaging times required by low-power systems have been shown to lead to biases in data, and indeed, our results showed strong disagreements on nights when the atmosphere was changing rapidly, such as on windy nights or when a storm system was entering the area. Improvements to the system to correct the major systematic biases are described.
Michael D. Obland, Kevin S. Repasky, Amin R. Nehrir, John L. Carlsten, Joseph A. Shaw, "Development of a widely tunable amplified diode laser differential absorption lidar for profiling atmospheric water vapor," Journal of Applied Remote Sensing 4(1), 043515 (1 March 2010). http://dx.doi.org/10.1117/1.3383156
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KEYWORDS
Absorption

Transmitters

Semiconductor lasers

Optical amplifiers

LIDAR

Sensors

Avalanche photodetectors

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