Diode-pumped long-pulse-length Ho:Tm:YLiF(4) laser at 10 Hz

High-repetition rate, single-frequency laser with a double Er:YAG ceramics ring cavity

A high pulse repetition frequency (PRF) single-frequency Er:YAG ceramic ring laser is demonstrated. A double-ceramics ring cavity both end-pumped by a 1532-nm fiber laser is also used to increase the pulse energy. The maximum single-frequency output energies are 21.0 mJ, 18.3 mJ, and 14.4 mJ at the PRF of 500 Hz, 750 Hz, and 1 kHz, respectively. Correspondingly, the pulse widths are 93.2 ns, 106.8 ns, and 130 ns. To the best of our knowledge, this is the highest energy at high PRFs obtained from a single-frequency injection-seeded Er:YAG ceramic laser.

Diode-pumped 2-μm pulse laser with noncomposite Tm,Ho:YLF rod conduction-cooled down to -80°C

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.

Diode-end-pumped continuously tunable single frequency Tm, Ho:LLF laser at 2.06 μm

We report on a laser diode-end-pumped continuously tunable single frequency Tm, Ho:LLF laser near room temperature. For transmission of 5%, the maximum single frequency output power of 221 mW at 2064.4 nm was obtained by using two uncoated etalons. The single frequency Tm, Ho:LLF laser operated on the fundamental transverse mode with an M2 factor of 1.13, and the output frequency could be tuned continuously near 1.5 GHz by angle tuning only of the 1 mm thick etalon. Furthermore, the influence of output coupler transmission on the laser performance was also investigated. The single frequency laser can be used as a seed laser for coherent Doppler lidar and differential absorption lidar systems.

Tunable, Q-switched Tm,Ho:LLF laser with a conductively cooled triangular prism rod

We have developed a conductively cooled, Q-switched 2 μm laser with a triangular-prism Tm,Ho:LLF rod. Using a fused-silica acousto-optic Q-switch, the laser produced an output energy of 30 mJ in a single Q-switched pulse at a pulse repetition frequency of 5 Hz. Although the laser rod had polished lateral surfaces, no parasitic oscillation occurred, even at the maximum pumping level. In addition, broadly tunable laser performance was achieved with a birefringent filter plate under relatively large output coupling. The laser could be continuously tuned from 2051 to 2069 nm. Measured tuning characteristics were in reasonable agreement with calculated results.

125-mJ diode-pumped injection-seeded Ho:Tm:YLF laser

We describe a diode-pumped, room-temperature Ho:Tm:YLF power oscillator with an optical-to-optical efficiency of 0.03. A Q -switched output energy of as much as 125 mJ at 6 Hz with a pulse width of 170 ns was obtained. Single-frequency, nearly transform-limited operation of the laser was achieved by injection seeding. Laser performance as a function of laser rod temperature and pump intensity was also investigated. The high power and high beam quality of this laser make it well suited for use as a coherent wind lidar transmitter on a space platform.