ABSTRACT
A 2 µm Ho-doped ytrrium lithium fluoride (Ho:YLF) laser end-pumped by a 1.94 µm Tm:fiber laser was developed. A laser system of a ring resonator oscillator and amplifier was operated at repetition rates of 200-5000 Hz at room temperature. The Q-switched outputs were 7.4 W at 5000 Hz and 4.25 W at 200 Hz. Injection seeding was applied to the ring resonator, and single-mode laser emission was obtained. The Tm:fiber-laser-pumped Ho:YLF laser was first used for Doppler wind lidar measurements, and wind profiles were obtained up to ranges of about 15 km in a range resolution of 96 m and an integration time of 1 s.
ABSTRACT
Q-switched operation of a diode-side-pumped, conduction-cooled Tm,Ho:YLF laser oscillator with 100-mJ output at a pulse repetition rate of 20 Hz and an eye-safe wavelength of 2-µm was achieved. The noncomposite Tm,Ho:YLF laser rod was conduction-cooled down to -80°C through thermal contact of In films from Cu heat sinks, and the laser diode arrays were conduction-cooled to approximately 20°C using Cu heat sinks in a vacuum container. A ring resonator of 3.86 m length with an acousto-optic Q-switch was used. The pulse width was 125 ns, and optical-to-optical efficiency was approximately 7% for an output of 100 mJ. The laser is used at 2.05 µm for applications of Doppler wind lidar measurements, CO2 differential absorption lidar measurements, and aerosol profiling.
ABSTRACT
A coherent 2 microm differential absorption and wind lidar (Co2DiaWiL) was developed to measure CO(2) concentration and line-of-sight wind speed. We conductively cooled a pumping laser head to -80 degrees C and diode arrays to approximately 20 degrees C. A Q-switched laser outputs an energy of 80 mJ (pulse width 150 ns (FWHM), pulse repetition frequency up to 30 Hz). CO(2) measurements made over a column range (487-1986 m) for 5 min accumulation time pairs achieved 0.7% precision. Line-of-sight wind speeds for ranges up to approximately 20 km and returns from a mountainside located 24 km away from the Co2DiaWiL were obtained.
