All solid-state CW Nd:LuVO<Subscript>4</Subscript>-LBO yellow-green laser under direct 888 nm pumping

We report a yellow-green laser at 544.5 nm generation by intracavity frequency doubling of a continuous wave (CW) laser operation of a 1089 nm Nd:LuVO₄ laser under in-band diode pumping at 888 nm. An LBO crystal, cut for critical type I phase matching is used for second harmonic generation of the laser. At an incident pump power of 17.9 W, as high as 3.81 W of CW output power at 544.5 nm is achieved. The optical-to-optical conversion efficiency is up to 21.3%, and the fluctuation of the yellow-green output power was better than 3.7% in the given 4 h.     

Efficient CW Nd:GdVO<Subscript>4</Subscript>-BiBO deep-blue laser at 456 nm under direct 888 nm diode laser pumping

We report an efficient laser emission on the 912 nm ⁴ F _3/2 to ⁴ I _9/2 transition in Nd:GdVO₄ under the pump with diode lasers at 888 nm. Continuous wave (CW) 4.91 W output power at 912 nm is obtained under 18.3 W of incident pump power; the slope efficiency with respect to the incident pump power was 57.5%. Moreover, intracavity frequency doubling with BiB₃O₆ (BiBO) nonlinear crystal yielded 1.33 W of deep-blue light at 456 nm.     

All-solid-state CW Nd:GdVO<Subscript>4</Subscript>-LBO red laser under direct 912 nm pumping

We report a red laser at 670.5 nm generation by intracavity frequency doubling of a continuous wave (CW) laser operation of a 1341 nm Nd:GdVO₄ laser under in-band diode pumping at 912 nm. An LBO crystal, cut for critical type I phase matching is used for second harmonic generation of the laser. At an incident pump power of 8.9 W, as high as 347 mW of CW output power at 670.5 nm is achieved. The fluctuation of the red output power was better than 3.7% in the given 30 min, and the beam quality factor M ² is 1.65.     

High efficiency 1341 nm Nd:GdVO<Subscript>4</Subscript> laser in-band pumped at 912 nm

A high-efficiency 1341 nm Nd:GdVO₄ laser in-band pumped at 912 nm is demonstrated for the first time. Using an all-solid-state Nd:GdVO₄ laser operating at 912 nm as pump source, 542 mW output was obtained with 1.14 W absorbed pump power. The slope efficiency with respect to the absorbed pump power was 56.6%, and the fluctuation of the output power was better than 2.6% in the given 30 min. The beam quality factor M ₂ is 1.15.     

High efficiency 1341 nm Nd:GdVO<Subscript>4</Subscript> bounce laser in-band pumped at 879 nm

A high-efficiency Nd:GdVO₄ bounce laser in-band pumped at 879 nm is demonstrated for the first time. From a side-pumped Nd:GdVO₄ crystal, 8.2 W output was obtained with 18.5 W absorbed pump power. Corresponding slope efficiency with respect to the absorbed pump power was 51.4%, and the beam quality factor M2 is 1.13 and 1.15 for tangential direction and sagittal direction, respectively. Effects of crystal’s doping concentration and temperature on laser power and conversion efficiency were also investigated.     

All solid-state continuous-wave intracavity frequency-doubled Nd:LuVO<Subscript>4</Subscript>-LBO red laser at 671.5 nm

We report for the first time a efficient compact red laser at 671.5 nm generation by intracavity frequency doubling of a continuous wave laser operation of a diode direct pumped Nd:LuVO₄ laser on the ⁴ F _3/2 → ⁴ I _13/2 transition at 1343 nm. An LBO crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an absorbed pump power of 16.2 W, as high as 4.3 W of continuous wave output power at 671.5 nm is achieved with 10-mm-long LBO. Comparative results obtained for the pump with diode laser at 808 nm, into the highly-absorbing ⁴ F _5/2 level, are given in order to prove the advantages of the 880 nm wavelength pumping.     

Diode single-end-pumped AO Q-switched Nd:GdVO<Subscript>4</Subscript> 266 nm laser

By simple extra-cavity frequency conversion, the performance of a diode single-end-pumped AO Q-switched Nd:GdVO₄/KTP/BBO 266 nm laser was demonstrated. Under the incident pump power of 14.32 W, the maximum average output power at 266 nm was 374 mW at the repetition of 20 kHz; the opticaloptical conversion efficiency was 2.6%. The corresponding pulse width was 5 ns, with the single-pulse energy and peak power calculated to be 18.7 μJ and 3.74 kW, respectively. The dependence of the operational parameters on the pump power was also investigated experimentally.     

Nd:GdVO<Subscript>4</Subscript> slab laser with line-shaped end-pumping profile operating at 912 nm

A continuous-wave laser with line-shaped end-pumping profile operating at 912 nm is presented. The maximum output power of 7.82 W is obtained, with a slop efficiency of 24.7% and beam quality factors of M _x ² ∼ 20, M _y ² ∼ 1.3. To the best of our knowledge, this is the first laser diode bar directly pumped Nd:GdVO₄ slab laser based on the quasi-three-level ⁴ F _3/2 → ⁴ F _9/2 transition in neodymium. Furthermore, we disclose that the experimental setups can be improved by inserting a plano-concave cylindrical lens in the cavity to form a new quasi-concentric resonator to improve die mode-matching in x-direction.     

diode-pumped single-frequency Tm:GdVO<Subscript>4</Subscript> laser at 1897.6 nm

A diode end-pumped Tm:GdVO₄ laser at room temperature is reported. The maximal output power of single-frequency is as high as 34 mW by using two uncoated fused etalons, which are respectively 0.05 mm thick YAG and 1mm thick quartz. We obtained the single frequency Tm:GdVO₄ laser at 1897.6 nm with the slope efficiency of 1.3%. The single-longitudinal-mode (SLM) laser can be used as a seed laser for coherent wind measurements and differential absorption LIDAR systems.     

Diode-pumped doubly Q-switched Nd:GdVO<Subscript>4</Subscript> laser

By using both an acoustooptical (AO) modulator and a Cr⁴⁺:YAG saturable absorber in the cavity, a diode-pumped doubly Q-switched Nd:GdVO₄ laser, which can generate short pulses with high peak powers and symmetric temporal profiles, has been demonstrated. A peak power of 3.05 kW with a corresponding pulse width of 16 ns has been achieved at an incident pump power of 7.7 W. A reasonable analysis about the experimental results has been given by considering the ground-state absorption and excited-state absorption of a Cr⁴⁺:YAG crystal.     

Cavity-dumped mode-locked Nd:GdVO<Subscript>4</Subscript> laser at low repetition rate

We report a cavity-dumped mode-locked Nd:GdVO₄ laser with semiconductor saturable absorber mirrors at low repetition rate. In this laser system, a single mode-locked laser pulse is generated, amplified and cavity-dumped by means of electro-optic modulator at 1 to 10 Hz repetition rate. The energy of the pulse is about 150 nJ and the pulse duration is determined to be 10 ps.     

All-solid-state CW Nd:LuVO<Subscript>4</Subscript>-LBO laser at 533 nm under direct 888 nm pumping

We report an efficient laser emission on the 1066 nm ⁴ F _3/2 to ⁴ I _11/2 transition in Nd:LuVO₄ under the pump with diode laser at 888 nm. Continuous wave (CW) 11.2 W output power at 1066 nm is obtained under 18.3 W of incident pump power; the slope efficiency with respect to the incident pump power was 71.9%. Moreover, intracavity frequency doubling with LiB₃O₅ (LBO) nonlinear crystal yielded 4.2 W of green light at 533 nm. An optical-to-optical efficiency with respect to the incident pump power was 23.0%.     

Room temperature diode-pumped 1875.1 nm Tm:GdVO<Subscript>4</Subscript> laser

A diode end-pumped single-frequency Tm:GdVO₄ laser at room temperature was reported. The maximal output power of single-frequency is as high as 66 mW by using two uncoated fused etalons, which are respectively 0.05 mm thick YAG and 1 mm thick quartz. We obtained the single frequency Tm:GdVO₄ laser at 1875.1 nm. The slope efficiency is 1.5%. The change of the lasing wavelength on temperature was also measured. The single-longitudinal-mode (SLM) laser can be used as a seed laser for coherent wind measurements and differential absorption LIDAR systems.     

A high power CW Ho,Tm:GdVO<Subscript>4</Subscript> laser

In this paper, we report a 22.7 W continuous wave (CW) diode-pumped cryogenic Ho( at %), Tm(3 at %):GdVO₄ laser. The pumping sources of Ho,Tm:GdVO₄ laser are two fiber-coupled laser diodes with fiber core diameter of 0.4 mm, both of them can supply 42 W power laser operating near 802 nm. For input pump power of 64.7 W at 802.5 nm, the output power of 22.7 W in CW operation, optical-to-optical conversion efficiency of 35.1% at 2.05 μm has been attained. The M ² factor was found to be 2.0 under an output power of 16.5 W.     

Continuous-wave simultaneous dual-wavelength operation at 912 nm and 1063 nm in Nd:GdVO<Subscript>4</Subscript>

A continuous-wave, diode-pumped Nd:GdVO₄ thin disk laser with simultaneous dual-wavelength emission at the 912 nm ⁴ F _3/2→⁴ I _9/2 quasi-three-level transition and the 1063 nm ⁴ F _3/2→⁴ I _11/2 four-level transition is demonstrated and analyzed. Output powers of 1.7 W at 912 nm and of 1.6 W at 1063 nm were achieved simultaneously from a 0.3-at.%, 300-μm thick Nd:GdVO₄ crystal that was multi-pass excited with 26.8 W of available diode pump power. Second harmonic generation to 456 nm with LiB₃O₅ yielded 0.96 W in 912 nm single-wavelength operation and 0.73 W in 912 nm/1063 nm dual-wavelength operation. PACS 42.55.Rz; 42.60.By; 42.65.Ky     

Continuous-wave Nd:GdVO<Subscript>4</Subscript>/LBO laser at 541.5 nm under diode pumping into the emitting level

We report a green laser at 541.5 nm generation by intracavity frequency doubling of a continuous wave (cw) laser operation of a 1083 nm Nd:GdVO₄ laser under 880 nm diode pumping into the emitting level ⁴ F _3/2. A LiB₃O₅ (LBO) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an incident pump power of 17.8 W, as high as 2.52 W of cw output power at 541.5 nm is achieved. The optical-to-optical conversion efficiency is up to 14.2%, and the fluctuation of the green output power was better than 3.6% in the given 30 min.     

Compact diode-directly-pumped passively mode-locked TEM<Subscript>00</Subscript> Nd:GdVO<Subscript>4</Subscript> laser at 1341 nm using a semiconductor saturable absorber mirror

We report on a compact 880-nm diode-directly-pumped passively mode-locked TEM₀₀ Nd:GdVO₄ laser at 1341 nm with a semiconductor saturable absorber mirror (SESAM) for the first time. Under the absorbed pump power of 14.6 W, the maximum output power of 1.27 W was obtained at the repetition rate of 85.3 MHz with the pulse width of 45.3 ps, corresponding to an optical-optical efficiency of 8.8% and the slope efficiency of 33.3%, respectively. The beam quality factor was measured to be M ² = 1.18, indicating a TEM₀₀ mode.     

Diode-pumped Nd:YVO<Subscript>4</Subscript>/Nd:YLF laser at 488 nm

We present a laser architecture to obtain continuous-wave blue radiation at 488 nm. A 808 nm diode-pumped the Nd:YVO₄ crystal emitting at 914 nm. A part of the pump power was then absorbed by the Nd:YVO₄ crystal. The remaining was used to pump the Nd:YLiF₄ (Nd:YLF) crystal emitting at 1047 nm. Intracavity sum-frequency mixing at 914 and 1047 nm was then realized in a BiB₃O₆ (BiBO) crystal to reach the blue radiation. We obtained a continuous-wave output power of 339 mW at 488 nm with a pump laser diode emitting 18.3 W at 808 nm.     

All solid-state CW orange-red laser at 620 nm

We report for the first time a continuous-wave (CW) orange-red radiation at 620 nm by intracavity sum-frequency generation of 1085-nm Nd:YVO₄ laser and 1444-nm Nd:YAG laser. Using type-II critical phase matching KTP crystal, 620-nm orange-red laser was obtained by 1085- and 1444-nm intra-cavity sum-frequency mixing, and output power of 223 mW was demonstrated. At the output power level of 223 mW, the output power stability is better than 3% and laser beam quality M ² factor is 1.32.     

Improvement of diode-end-pumped 912 nm Nd:GdVO<Subscript>4</Subscript> laser performance based on microchannel heat sink

To solve the thermal dissipation problem in diode-end-pumped solid state lasers and improve the performance of 912 nm Nd:GdVO₄ lasers, a novel microchannel heat sink is designed and used in the experiments. Heat-transfer coefficients for the common heat sink and microchannel heat sink are calculated. The results obtained for the heat-transfer coefficient for the heat sink with a channel width of 0.2 mm is almost 5 times higher than that of the common one. The heat resistance for the novel heat sink is analyzed. Simulation results show that the maximum temperature in the laser crystal is reduced by 19°C at an absorbed pump power of 24.0 W, and the heat transfer ability significantly increases if the microchannel heat sink is used. Experimental results also indicate that the performance for a 912 nm laser is improved significantly using the novel heat sink, especially from the aspects of laser-beam quality and power scaling.