A Novel 1,066 nm Nd:Gd<Subscript>0<Emphasis Type="Italic">.</Emphasis>69</Subscript>Y<Subscript>0<Emphasis Type="Italic">.</Emphasis>3</Subscript>NbO<Subscript>4</Subscript> Passively <Emphasis Type="Italic">Q</Emphasis>-Switched Pulse-Burst Laser

We demonstrate for the first time a Cr⁴⁺:YAG passively Q-switched 1066 nm pulse-burst laser under 879 nm direct pump with a novel Nd:Gd_0.69Y_0.3NbO₄ crystal. The output laser characteristics with different pump repetition rates and different Cr⁴⁺:YAG initial transmission are studied. Without the Cr⁴⁺:YAG, we obtain a maximum output energy of 2.55 mJ at an absorbed pump energy of 5.79 mJ with the highest 48% slope efficiency. The pulse-burst laser contains a maximum of 7 pulses for a Cr⁴⁺:YAG initial transmission of 55% and a pump repetition rate of 1 kHz. The single-pulse energy and narrowest pulse width reach 160 μJ and 5.5 ns at 38.2 kHz, with a peak power of 32 kW.     

Upconversion CW laser at 284 nm in a Nd:YAG-pumped double-cladding thulium-doped ZBLAN fiber laser

A successful continuous-wave (CW) ultraviolet (UV) laser in a Tm⁺³-doped ZBLAN fiber, operated at 284 nm (¹ I ₆ → ³ H ₆ transition of Tm⁺³) is demonstrated. The excitation uses a four-step upconversion scheme. The pump source is a Nd:YAG laser operated at 1.064 μm. A laser output power of 42 μW continuous wave was obtained for 590 mW of the launched pump power. The slope efficiency with respect to the launched pump power was measured to be 9%. Ultraviolet (at 365 nm) and visible (at 453 and 480 nm) radiation was also observed.     

Diode-pumped quasi-three-level Nd:CLNGG laser at 928 nm

We describe the output performances of the 928 nm ⁴ F _3/2 → ⁴ I _9/2 transition in Nd:CLNGG under diode-laser pumping. An end-pumped Nd:CLNGG crystal yielded 1.3 W of continuous-wave output power for 17.8 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power was 11.2%. Furthermore, with 17.8 W of diode pump power and the frequency-doubling crystal LiB₃O₅ (LBO), a maximum output power of 260 mW in the blue spectral range at 464 nm has been achieved. The blue output power stability over 4 h is better than 3.2%.     

High-Power Diode-End-Pumped Slab Composite Tm:YLF Compact Laser

We design a continuous-wave Tm:YLF laser with a composite slab crystal end-pumped by two fiber-coupled laser diodes at room temperature. We achieve a maximum continuous wave output power of 105 W for the bonded slab Tm:YLF laser; the corresponding slope efficiency is 47.7% and the optical-to-optical conversion efficiency is 42.0% with respect to the incident pump power. The laser operated at 1,907.5 nm with a beam quality factor of M² ～3.2 at the highest output power.     

Efficiency intracavity frequency-doubled Nd:Y<Subscript>0.36</Subscript>Gd<Subscript>0.64</Subscript>VO<Subscript>4</Subscript>-LBO green laser at 532 nm with direct pumping

We report an efficient laser emission on the 1064 nm ⁴ F _3/2 to ⁴ I _11/2 transition in mixed vanadate crystal Nd:Y_0.36Gd_0.64VO₄ under the pump with diode laser at 880 nm. Continuous wave (CW) 10.7 W output power at 1064 nm is obtained under 17.8 W of incident pump power; the slope efficiency with respect to the incident pump power was 71.2%. Moreover, intracavity frequency doubling with LiB₃O₅ (LBO) nonlinear crystal yielded 4.6 W of green light at 532 nm. An optical-to-optical efficiency with respect to the incident pump power was 25.8%.     

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.     

Stable and Efficient Pulsed Mid-Infrared Laser Generation from an Er<Superscript>3+</Superscript>-Doped ZBLAN Fiber Laser

We demonstrate a stable and efficient passively Q-switched 2.8 μm Er³⁺-doped ZBLAN fiber laser with a broadband semiconductor saturable absorber mirror. Enabled by the broadband optical modulator, the stable Q-switched fiber laser can deliver a maximum average power over 700 mW with corresponding per-pulse energy of 8.19 μJ and a pulse width of 1.3 μs at a repetition rate of 88.6 kHz under an incident pump power of 3.8 W. In addition, the slope efficiency can reach 22.5%. To the best of our knowledge, this is the highest reported slope efficiency for the passively Q-switched Er³⁺-doped ZBLAN fiber laser.     

Voltage-on-Type RTP Pockels Cell for <Emphasis Type="Italic">Q</Emphasis>-switch of an Er:YAG Laser at 1,617 nm

We report a resonantly diode-pumped electro-optic Q-switched Er:YAG laser operating at 1,617 nm using a voltage-on-type rubidium titanyl phosphate (RTP) Pockels cell as the modulator. The Er:YAG laser operates at a very stable Q-switching mode with a per pulse energy yield of 1.5 mJ and a pulse duration of 114 ns at 1 kHz PRF under an incident pump power of 21.6 W.     

Diode-pumped Nd:LuVO<Subscript>4</Subscript>-LBO green laser at 533 nm

We report a continuous-wave (CW) coherent green radiation at 533 nm by intracavity frequency doubling generation of 1066 nm Nd:LuVO₄ laser. With incident pump power of 18.2 W, output power of 4.3 W at 533 nm has been obtained using a 5 mm-long LBO crystal. The optical conversion efficiency was up to 23.6%. At the output power level of 4.3 W, the output stability is better than 3%. The beam quality M² values were equal to 1.13 and 1.21 in X and Y directions, respectively.     

LD end-pumped c-Cut Nd:YVO<Subscript>4</Subscript>/KTP self-Raman laser at 560 nm

Intra-cavity sum frequency generation (SFG) of c-cut Nd:YVO₄ self-Raman laser was investigated for the first time. A 4 × 4 × 10 mm³ KTP crystal with a type-II phase-matching cutting angle (θ = 83.4°, φ = 0°) was used for SFG between the fundamental light at 1066 nm and first-Stokes light at 1178 nm. The laser system with different curvature radii of output couplers and different pulse repetition frequencies were investigated. At a pump power of 14 W and pulse repetition frequency of 20 kHz, the average output power of yellow-green laser at 560 nm up to 840 mW was achieved, corresponding to a slope efficiency of 7.6% and a conversion efficiency of 6% with respect to diode pump power.     

All-solid-state continuous-wave frequency-doubling Nd:LuVO<Subscript>4</Subscript>/GBCOB laser at 533 nm

We report an efficient intracavity second-harmonic generation (SHG) at 1066 nm in a non-linear optical crystal, GdCa₄O(BO₃)₃ (GdCOB), performed with a diode end pumped continuous-wave (CW) Nd:LuVO₄ laser. In the case of a laser with a Nd:LuVO₄ crystal frequency-doubled with a GdCOB crystal cut for type I frequency doubling. A CW SHG output power of 5.18 W has been obtained using a 10 mm long GCOB crystal. The optical conversion efficiency with respect to the incident pump power was 28.5%.     

Diode-Pumped Yb:S-FAP Thin-Disk Laser Operating at 985 nm and the Second-Harmonic Generation at 492.5 nm

We report a diode-pumped continuous-wave (CW) thin-disk Yb³⁺-doped Sr₅(PO₄)₃F (Yb:S-FAP) laser operating at 985 nm. We achieve a power of 4.34 W at 980 nm in the CW operation regime with a fiber-coupled laser diode emitting 17.2 W at 914 nm. Furthermore, we demonstrate intracavity second-harmonic generation in the continuous-wave mode with a power of 893 mW at 492.5 nm using a BiB₃O₆ (BiBO) nonlinear crystal. The fluctuation of the blue output power was better than 3.57%. The M₂ factors are about 1.15 and 1.18 in the X and Y directions, respectively.     

Diode-pumped CW Nd<Superscript>3+</Superscript>:YAlO<Subscript>3</Subscript> laser at 1339 nm

A diode-pumped Nd³⁺:YAlO₃ (Nd:YAP) laser emitting at 1339 nm is described. At the incident pump power of 17.8 W, as high as 3.4 W of continuous-wave (CW) output power at 1339 nm is achieved. The slope efficiency with respect to the incident pump power was 23.6%. The output power stability over 60 min is better than 3.5%. The laser beam quality M ² factor is 1.33.     

A High-Power,Long-Wavelength Infrared ZnGeP<Subscript>2</Subscript> Opo Pumped by a <Emphasis Type="Italic">Q</Emphasis>-Switched Tm,Ho:GdVO<Subscript>4</Subscript> Laser

We report a high-power, long-wavelength infrared ZnGeP₂ (ZGP) optical parametric oscillator (OPO) pumped by a Q-switched Tm,Ho:GdVO₄ laser. The wavelength tuning range of 7.8–9.9 μm is realized by rotating the external angle of the ZGP crystal. We obtain an output power over 30 mW across the whole wavelength range and achieve a 1.71 W output power at 8.08 μm by transmitting the OPO parameters, corresponding to an idler laser slope efficiency of 12.1%.     

Diode-pumped Nd<Superscript>3+</Superscript>:YAl<Subscript>3</Subscript>(BO<Subscript>3</Subscript>)<Subscript>4</Subscript> laser at 1338 nm

A high-power diode -pumped Nd³⁺:YAl₃(BO₃)₄ (Nd:YAB) laser emitting at 1338 nm is described. At the incident pump power of 9.8 W, as high as 734 mW of continuous-wave (CW) output power at 1338 nm is achieved. The slope efficiency with respect to the incident pump power was 9.0%. To the best of our knowledge, this is the first demonstration of such a laser system. The output power stability over 60 min is better than 2.6%. The laser beam quality M ² factor is 1.21.     

Efficient intracavity frequency-doubled Nd:GdVO4-LBO red laser at 670.5 nm under direct 888 nm pumping

We report an efficient laser emission on the 1341 nm ⁴ F _3/2 to ⁴ I _13/2 transition in Nd:GdVO₄ under the pump with diode lasers at 888 nm. Continuous wave (CW) 6.58 W output power at 1341 nm is obtained under 18.3 W of incident pump power; the slope efficiency with respect to the incident pump power was 45.1%. Moreover, intracavity frequency doubling with LiB₃O₅ (LBO) nonlinear crystal yielded 1.77 W of red light at 670.5 nm.     

Efficiency intracavity frequency-doubled Nd:CNGG-LBO green laser at 530.5 nm under direct 885 nm pumping into the emitting level

We report an efficient laser emission on the 1061 nm ⁴ F _3/2 to ⁴ I _11/2 transition in Nd:CNGG under the pump with diode laser at 885 nm. Continuous wave (CW) 5.4 W output power at 1061 nm is obtained under 17.4 W of incident pump power; the slope efficiency with respect to the incident pump power was 36.2%. Moreover, intracavity frequency doubling with LiB₃O₅ (LBO) nonlinear crystal yielded 1.75 W of green light at 530.5 nm. An optical-to-optical efficiency with respect to the incident pump power was 10.1%.     

A Tm:YLF End-Pumped Acousto-Optic <Emphasis Type="Italic">Q</Emphasis>-Switched Ho:YAG Laser

We report an acoustic Q-switched Ho:YAG laser end-pumped by a 1,908 nm Tm:YLF laser. The doping concentration of Ho:YAG crystal is 2 at.%, and dimensions ø5×20 mm. We measure the pulsedlaser output characteristics of the Ho:YAG laser at different repetition rates (RF). Under optimum experimental conditions, the high-power 2.1 μm output power reaches 4.17 W at a given pump power of 13.25 W and repetition frequency of 8.0 kHz. For a slope efficiency of 16.88%, the corresponding optical-to-optical conversion efficiency reaches 31.47%. We obtain a minimum single pulsed energy of 7.36 mJ and a pulse width of 52.8 ns at a pump power of 10.52 W and repetition rate of 0.5 kHz, with a peak power of 139 kW.     

Simultaneous dual-wavelength operation at 1.06 and 1.34 μm in Nd-vanadate laser crystals

Output performances of Nd-vanadate lasers with simultaneous dual-wavelength emission on the 1.06-μm ⁴ F _3/2 → ⁴ I _11/2 transition and the ⁴ F _3/2 → ⁴ I _13/2 transition at 1.34 μm are discussed. The design uses a linear resonator for emission at 1.06 μm and an L-type folded resonator for the 1.34-μm wavelength, and the ratio between the power of a single wavelength and the total power is adjusted by the choice of the output mirror transmissions. A continuous-wave (CW) Nd:GdVO₄ laser with total output power in the range of 3.9 to 6.8 W and the corresponding ratio of the output power at 1.06 μm to the total output power between 0.26 and 0.97 is realized. It is also shown that in comparison with the pump at 808 nm, the pump directly into the ⁴ F _3/2 emitting level at 879 nm improves the total output power. Furthermore, a Nd:GdVO₄ laser with simultaneous emission at 1.06 and 1.34 μm and that generates also green light at 0.53 μm by intracavity frequency-doubling with LiB₃O₅ (LBO) nonlinear crystal is demonstrated.     

High-Pulse-Energy Passively <Emphasis Type="Italic">Q</Emphasis>-Switched 1,123 nm Laser with a Nd:GdYAG Mixed Garnet as Laser Medium

We demonstrate a diode-pumped passively Q-switched Nd:GdYAG mixed garnet laser at 1,123 nm. A Cr⁴⁺:YAG crystal with an initial transmission of 97% is used as the saturable absorber. The maximum average output power is 1.05 W at an absorbed pumping power of 8.12 W. A single-pulse energy can reach up to 78.9 μJ, with a corresponding pulse repetition rate of 13.3 kHz.