Lei Guo

1319 nm and 1338 nm dual-wavelength operation of LD end-pumped Nd:YAG ceramic laser

In this paper, we demonstrate the efficient 1.3 um dual-wavelength operation of LD end-pumped Nd:YAG ceramic laser. With a plano-concave cavity, a maximum continuous-wave dual-wavelength output power of 5.92 W is obtained under an incident pump power of 20.5 W, giving a slope efficiency of 30.3% and an optical-optical conversion efficiency of 29.0%. With Co(2+):LaMgAl(11)O(19) crystal as the saturable absorber, the passively Q-switched dual-wavelength operation is achieved for the first time to our knowledge. The maximum passively Q-switched average output power is 226 mW, the minimum pulse width is 15 ns, and the highest pulse repetition rate is 133 kHz.

Dual-wavelength Nd:YAG crystal laser at 1074 and 1112 nm

We reported an efficient laser-diode (LD) end-pumped CW dual-wavelength Nd:YAG crystal laser operating at 1074 and 1112 nm simultaneously, for the first time to our knowledge. The maximum output power was 3.15 W with an optical conversion efficiency of 23.6%. Considering the broad absorption of carbonylhemoglobin and hemoglobin located at about 538 and 555 nm, respectively, we proposed that this dual-wavelength laser is an important source for detecting carbon monoxide poisoning by simple frequency doubling.

Continuous-wave tri-wavelength operation at 1064, 1319 and 1338 nm of LD end-pumped Nd:YAG ceramic laser.

We demonstrated a laser-diode (LD) end-pumped continuous-wave (CW) tri-wavelength Nd:YAG ceramic laser operating at 1064, 1319 and 1338 nm. For the 1064 nm laser, one of the Nd:YAG polished end faces was used as the output coupler. As references, Nd:YVO(4) and Nd:YAG crystal lasers were also investigated under the same structure. We found that the maximum output power came from Nd:YAG ceramic which was 1.74 W, corresponding an optical conversion efficiency of 16.3%. Using a three mirror cavity, we realized efficient multi-wavelength operation at (4)F(3/2)-(4)F(11/2) and (4)F(3/2)-(4)F(13/2) transitions for Nd:YAG ceramic, simultaneously. The maximum output power was 3.2 W, which included 1064, 1319, and 1338 nm three wavelength, and the optical conversion efficiency was 30%.

Thermal, spectroscopic, and laser characterization of Nd:LuxY1-xVO4 series crystals

A series of Nd:LuxY1-xVO4 (x = 0.10, 0.26, 0.41, 0.61, 0.67, 0.80) mixed laser crystals were grown and researched systematically, for the first time to our knowledge. Their thermal properties were investigated, including the specific heat, thermal expansion, thermal conductivity and the material constant. Their spectral properties were measured and their spectral parameters were calculated by J-O theory, including the absorption spectrum, emission spectrum, fluorescence lifetime and emission cross section. In CW laser operation, a maximum output power of 3.1 W was obtained from the Nd:Lu0.10Y0.90VO4 mixed crystal, corresponding to an optical conversion efficiency of 51.7 %, and a slope efficiency of 59.8 %. When Cr:YAG crystal was used as the saturable absorber, passively Q-switched pulse laser operation was achieved for Nd:LuxY1-xVO4 series crystals. The best pulse performance came from Nd:Lu0.10Y0.90VO4 crystal, with the maximum pulse energy of 169 μJ and the highest peak power of 26.4 kW.

Continuous-wave and passively Q-switched Nd:LYSO lasers

Continuous-wave (CW) and passively Q-switched performance of a Nd-doped oyorthosilicate mixing crystal, (Nd0.005Lu0.4975Y0.4975)2SiO5 (Nd:LYSO), were reported. As a result, new dual-wavelength all-solid-state lasers at 1075 and 1079 nm were achieved. When the absorbed pump power was 3.87 W, the CW laser produced 1.1 W output, corresponding to an optical conversion efficiency of 28.4% and a slope efficiency of 32.4%. By using a Cr4+:YAG wafer as the saturable absorber, we achieved Q-switching operation of Nd:LYSO crystal. The maximal average output power, shortest pulse width, largest pulse energy and highest peak power were measured to be 294 mW, 27.5 ns, 34.3 μJ and 1.18 kW, respectively. By difference frequency, these dual-wavelength lasers have potential applications for the generation of a broadband coherent radiation from 0.7–1.3 THz.

Efficient dual-wavelength operation of Nd:LYSO laser by diode pumping aimed toward the absorption peak

By aiming the pump wavelength of the laser diode to the absorption peak at 811 nm of the (Nd0:005Lu0:4975Y0:4975)2SiO5 (Nd:LYSO) crystal, an efficient dual-wavelength operation at 1,075 and 1,079 nm is obtained. The maximum output power is 702 mW when the incident pump power is 2.53 W, corresponding to an optical conversion efficiency of 27.7% and a slope efficiency of 37.0%.

Passively Q-switched Nd:YAG ceramic laser towards large pulse energy and short pulse width

A large pulse energy and high peak power passively Q-switched ceramic neodymium-doped yttrium aluminum garnet (Nd:YAG) laser has been demonstrated with Cr4+:YAG crystals as the saturable absorbers. By employing a continuous wave (CW) laser-diode (LD) as the pump source, as high as 11.3 W CW output power of 1064 nm was obtained under the pump power of 21.6 W, with an optical conversion efficiency of 52.3%. Inserting different initial transmissions Cr4+:YAG as saturable absorbers, under the incident pump power of 15.6 W, the largest pulse energy, shortest pulse width, and highest peak power are measured to be 188 µJ, 3.16 ns, and 59.5 kW, respectively. As we has known, this is the best passively Q-switched results ever reported by Nd:YAG ceramic material.

6.5-ns actively Q-switched Nd:YVO4 laser operating at 1.34 \mu m

With a plano-concave cavity, diode-pumped continuous-wave (CW) and actively Q-switched Nd:YVO4 laser operating at 1.34 µm is demonstrated. Maximum CW output power of 4.76 W and Q-switched average output power of 2.64 W are obtained with output coupler (transmission T=3.9%). For the Q-switching operation, the theoretically calculated pulse energy and pulse width, with a pulse repetition frequency (PRF) range of 5-40 kHz, coincide with the experimental results. With a T=11.9% output coupler, the maximum peak power of 24.3 kW and minimum pulse width of 6.5 ns are obtained when the PRF is 10 kHz. To the best of our knowledge, this is the shortest actively Q-switched pulse duration ever obtained in a 1.3-µm Nd-doped vanadate laser.

A diode-pumped passively Q-switched c-cut Nd:Lu0.1Y0.9VO4 laser

The continuous wave and pulsed laser performances of a laser-diode-end-pumped c-cut Nd:Lu0.1Y0.9VO4 crystal have been demonstrated for the first time. The small emission cross section and appropriate upper level lifetime result in the c-cut Nd:Lu0.1Y0.9VO4 crystals having excellent pulsed laser performance. When the pulse repetition rate was 6.4 kHz, the shortest pulse width, the largest pulse energy and the highest peak power were found to be 1.9 ns, 104.7 μJ and 55.1 kW, respectively, using a Cr4+:YAG crystal as the saturable absorber. These results were much better than those for an a-cut Nd:Lu0.1Y0.9VO4 crystal under the same conditions.

Continuous-wave and Passively Q-switched c-cut Nd:CaYAlO4 Laser at 1.08 µm

We demonstrated an efficient high-power continuous-wave (cw) and passively Q-switched disordered c-cut Nd:CaYAlO4 laser at 1.08 um. Continuous-wave output power of 3.26 W was obtained with an optical conversion efficiency of 25.9% and a slope efficiency of 28.5%. In the passive Q-switching operation, the highest average output power, the shortest pulse width, largest pulse energy and highest peak power were achieved to be 2.61 W, 11.37 ns, 45.5 μJ and 2.43 kW, respectively, with Cr4+:YAG crystal as the saturable absorber.