TY  - THES
T1  - A high-power laser transmitter for ground-based and airborne water-vapor measurements in the troposphere
A1  - Schiller,Max
Y1  - 2010/06/09
N2  - A gain-switched high-power single-frequency Ti:sapphire laser was developed. It is pumped with a frequency-doubled diode-pumped Nd:YAG laser. The laser fulfills the requirements for a transmitter of a water-vapor differential absorption lidar (DIAL), intended for accurate high temporally- and spatially-resolved measurements from the ground to the upper troposphere. The laser was developed using thermal, resonator-design, spectral, and pulse-evolution models. There were layouts assembled for operation at 935 nm and 820 nm optimized for airborne and groundbased measurements, respectively.
A birefringent filter and an external-cavity diode laser as an injection seeder are controlling the spectral properties of the transmitter. With a frequency stability of < 60 MHz rms, an emission bandwidth of < 160 MHz, and a spectral purity of > 99.7 %, the total error from the laser properties is smaller than 5 % for water-vapor measurements in the troposphere. The laser beam profile is near-Gaussian with M2 < 2. The achieved laser power was 4.5 W at 935 nm and 7 W at 820 nm at repetition rate of 250 Hz. These values are the highest reported for a single-frequency Ti:sapphire laser.
As a part of a ground-based water-vapor DIAL system, the transmitter was deployed during the measurement campaign COPS (Convective and Orographically-induces Precipitation Study). Comparisons with radiosondes confirmed a high precision of the acquired water-vapor day- and nighttime measurements.
KW  - DIAL 
KW  - Titan-Saphir-Laser
KW  -  Abstimmbarer Laser
KW  - Pumpen <Laser>
KW  - Einmodenlaser
CY  - Hohenheim
PB  - Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim
AD  - Garbenstr. 15, 70593 Stuttgart
UR  - http://opus.uni-hohenheim.de/volltexte/2010/454
ER  -