B. Q. Yao

Diode pumped operation of tm, Ho:YAP microchip laser

Single-wave length operation of a c-cut Tm (5%), Ho (0.3%):YAP microchip laser pumped by a fiber-coup led diode-laser was reported. Under cryogenic temperature, the output power of 188 mW was obtained under the incident power of 2230 mW, corresponding to the slope efficiency was 12.2%. As much as 168 mW output and slope efficiency of 5.7% was obtained under the pump power of 3400 mW at 291 K. In addition, a maximum single-wave length output power of 60 mW at wavelength of 2130.2 nm and 14 mW at wavelength of 2102.4 nm is demonstrated under 77 and 291 K, respectively.

Single-frequency, Q-switched Ho:YAG laser at room temperature injection-seeded by two F–P etalons-restricted Tm, Ho:YAG laser

We demonstrated a 1.91 μm pumped, injection-seeded Q-switched Ho:YAG laser operating at room temperature. By inserting two Fabry-Perot etalons into the laser cavity, single-frequency Tm, Ho:YAG seed lasing was achieved at a wavelength of 2090.9 nm, with a typical output power of 60 mW. Single-frequency, nearly transform-limited Q-switched operation of the Ho:YAG laser was achieved by injection seeding. The output energy of the single-frequency Q-switched pulse is 7.6 mJ, with a pulse width of 132 ns and a repetition rate of 100 Hz. We measured the pulse spectrum, half-width of which was 3.5 MHz, by a heterodyne technique.

Room temperature single-frequency output from a diode-pumped Tm,Ho:YAP laser

Single-frequency operation in the range of 2102.45-2102.54 nm and 2130.72-2130.82 nm is demonstrated from a Tm,Ho:YAP laser at room temperature. To our knowledge, this is the first time a room temperature single-frequency Tm,Ho:YAP laser of up to 72.6 mW at 2102.5 nm with Fabry-Perot etalons has been obtained. Regulating the elevation angle of the two etalons, 42.0 mW at 2130.8 nm was obtained. The single-longitudinal-mode laser can be used as a seed laser for coherent wind measurements and differential absorption lidar systems.

High efficient double end-pumped b-cut Tm,Ho:YAlO3 laser

High efficient continuous wave (CW) and acousto-optical (AO) Q-switched operation of a b-cut Tm,Ho:YAlO3 (Tm,Ho:YAP) laser are reported in the paper. The Tm,Ho:YAP crystal was cooled by liquid nitrogen and pumped by a fiber-coupled laser diode (LD). Different pump wavelengths were tried in the experiment. An 8.36-W output power was acquired at 2.12 μm in the CW operation with an optical-optical conversion efficiency of 33.3%, and an 8.14-W average power was obtained at the pulse repetition frequency (PRF) of 10 kHz with an optical-optical conversion efficiency of 32.4%.

RTP Q-switched 2 μm Tm,Ho:GdVO4 Laser

In this paper, we report the performance of a diode-pumped cryogenic Tm (5 at %), Ho (0.5 at %):GdVO4 laser with an RTP pockel cell Q-switch at different pulse repetition rate including 300 Hz, 500 Hz, 1 kHz, and 10 kHz. At the pump power of 6.96 W, the maximum output of 1.7 mJ with a pulse width of 28 ns was achieved under 300 Hz repetition rate, corresponding to a peak power of 61 kW. To the best of our knowledge, this is the first time that RTP was used as a Q-switch generator in the 2 μm Tm,Ho:GdVO4 laser.

Diode-pumped single-frequency Tm:YAG laser with double etalons

A diode end-pumped single-frequency Tm:YAG laser at room temperature is reported. The maximal output power of single-frequency is as high as 60 mW by using two uncoated fused YAG etalons, which are respectively 0.1 and 1.0 mm thick. We obtained a single frequency Tm:YAG laser at 2013.91 nm. The change of the lasing wavelength on temperature was also measured. The single-longitudinal-mode laser can be used as a seed laser for coherent wind measurements and differential absorption LIDAR systems.

Efficient Q-switched Ho:GdVO 4 laser resonantly pumped at 1942 nm

An efficient 2 μm room-temperature Q-switched Ho:GdVO4 laser end-pumped by a 1942 nm Tm-fiber laser is demonstrated. To our knowledge, this is the first report of Q-switched performance of Ho:GdVO4 crystal. A maximum CW output power of 6.85 W under the absorbed pump power of 24.1 W was obtained with a slope efficiency of 39.5% at a temperature of 17°C. With the same absorbed pump power, a maximum output energy per pulse of about 0.9 mJ and minimum pulse width of 4.7 ns were obtained at the pulsed repetition frequency (PRF) of 5 kHz, corresponding to a peak power of approximately 187.2 kW.

A Cr:ZnS saturable absorber for a Tm:YLF pumped passively Q-switched Ho:YAG laser

A passively Q-switched Tm:YLF pumped Ho:YAG laser using Cr2+:ZnS as a saturable absorber is reported in this letter. A single pulse energy as high as 2.47 mJ is generated. The maximum average power reaches 16.6 W at a repetition rate of 10.4 kHz. The pulse durations are between 35 and 40 ns.

Room temperature single longitudinal mode Tm,Ho:Yap microchip laser at 2102.6 nm

Room temperature single-longitudinal-mode operation of a c-cut Tm(5%), Ho(0.3%):YAP microchip laser pumped by a fiber-coupled diode-laser is reported. An incident pump power of 3.06 W is used to generate the maximum single-frequency output power of 42 mW at 2102.6 nm, corresponding to optical-to-optical conversion efficiency of 1.4%. To the best of our knowledge, this is the first time to report of Tm,Ho:YAP microchip laser operation on single-frequency at room temperature.

Diode-pumped Q-switched Tm:LuAG ring laser operation at room temperature

Abstract2-μm lasers with high pulse energy and long pulse width of hundreds of nanoseconds are needed urgently in the accurate wind velocity lidar systems. This paper presented the acoustic-optical Q-switched Tm:LuAG laser performance in a pulsed-laser-diode end-pumping figure-eight ring resonator structure. Pulse energy and pulse width are investigated with the increasing of the incident pump energy at different repetition rate operation. Maximum energy of 3.3 mJ with the pulse width of 199 ns and 1.8 mJ with pulse width of 293 ns are obtained at the repetition rate of 20 and 50 Hz, respectively. Under Q-switched operation, the peak output wavelength is 2.022 μm at all time, and the beam quality factors are lower than 2 times diffraction-limited measured by a knife-edge traveling method.