High Power Continuous-Wave and Acousto-Optic Q-Switched Nd：GdVO4 Laser Operated at 912 nm

We present a high power and efficient operation of the ^4F3/2 → ^4I9/2 transition in Nd：GdVO4 at 912nm. In the cw mode, the maximum output power of 8.6 W is achieved when the incident pump power is 40.3 W, leading to a slope efficiency of 33.3% and an optical-optical efficiency of 21.3%. To the best of our knowledge, this is the highest cw laser power at 912nm obtained with the conventional Nd：GdVO4 crystal. Pulsed operation of 912nm laser has also been realized by inserting a small aeousto-optie （A-O） Q-Switch inside the resonator. As a result, the minimal pulse width of 20ns and the average laser power 1.43 W at the repetition rate of lOkHz are obtained, corresponding to 7.1 kW peak power. We believe that this is the highest laser peak power at 912nm. Furthermore, duration of 65ns has also been acquired when the repetition rate is 100 kHz.     

End-Pumped Tm:YAG Ceramic Slab Lasers

Lasers from a Tm：YAG slab is end-pumped by continuous-wave output of the Tm：YAG ceramic ceramic am~e reported for the t~rst time to our best knowledge. The Tm：YAG ceramic a laser diode with central wavelength 792nm. At room temperature, the maximum power is 4.5 W, and the sloping efficiency is obtained to be 20.5%. The laser spectrum is centered at 2015nm.     

A Compact All-Solid-State 630-ps 9.43-kHz High Power Nd：YAG/Nd：YVO4 Hybrid Laser System

We present a simple and compact design for an all-solid-state laser amplifier system which can output 9.43-kHz 630-ps, 3.5-W pulse trains under 20 W absorbed pumping power. The excellent matching between the repetition of its seed source and the fluorescence lifetime of the amplifying medium makes it quiet efficient for the four-pass amplifier to be pumped in cw mode without need of any synchronization device between the oscillator and the amplifier. The entire setup just covers an area of 55 × 25 cm^2. The output average power fluctuation is less than ±1.5% within 10min and 3% within 6h.     

Diode End-Pumped Passively Q-Switched Nd^3＋：GdVO4 Self-Raman Laser at 1176 nm

A compact diode-end-pumped passively Q-switched Nd^3＋ ：GdVO4/C^r4＋ ：YAG self-Raman laser at 1176 nm is demonstrated. When the To = 80% Cr^4＋：YAG saturable absorber is inserted into the cavity, the maximum Rtaman laser output reaches 175 mW with 3.8 W incident pump power. The optical conversion from incident to the Raman laser is 4.6% and the slope efficiency is 6.5%. The pulse energy, duration, and repetition frequency of the first stokes laser are 4.5μJ, 1.8 ns, and 38.5 kHz, respectively. There is strong blue emission （about 350- 400nm） can be observed in the Nd^3＋ ：GdVO4 crystal when the process of stimulated Raman scattering occurs, which is induced by the upconversion of the Nd^3＋ ions.     

A Bidirectional, Diode-Pumped, Passively Mode-Locked Nd：YVO4 Ring Laser with a Low-Temperature-Grown Semiconductor Saturable Absorber Mirror

We report the operation of a bidirectional picosecond pulsed ring Nd：YVO4 laser based on a low-temperaturegrown semiconductor saturable absorber mirror. Except for the laser crystal, the six-mirror ring laser cavity has no intra-cavity elements such as focusing lens or mirror. The bidirectional mode locked pluses are obtained at the repetition rate of 117.5 MHz, pulse duration of 81 ps, power of 2 × 200 mW.     

Efficient Diode-Pumped Tm：YALO3 Laser with a Pump Recycling Scheme

By using a pump recycling configuration, the maximum power of 8.1 W in the wavelength range 1.935-1.938 μm is generated by a 5-ram long Tm：YAIOa （4 at.%） laser operating at 18℃ with a pump power of 24 W. The highest slope efficiency of 42% is attained, and the pump quantum efficiency is up to 100%. The Tm：YAlO3 laser is employed as a pumping source of singly-doped Ho（1%）：GdV04 laser operating at room temperature, in which continuous wave output power of greater than 0.2 W at 2.05/μm is achieved with a slope efficiency of 9%.     

Nd:YAG Lasers Operating at 1064nm and 946nm by Direct Pumping and Thermally Boosted Pumping

We demonstrate a 1064nm Nd：YAG laser by directly pumping into the upper lasing level with a tunable Ti：sapphire laser. The valid wavelength is demonstrated at 868.3nm, 875.2nm, 883.8nm, and 885.5nm, respectively. To our knowledge, this is the first time that 1064nm Nd：YAG laser pumped by 875.2nm laser. In addition, laser wavelength at 946 nm is also generated by direct pumping together with traditional pumping.     

Sixth Harmonic of A Nd：YVO4 Laser Generation In KBBF for ARPES

We report that a deep ultraviolet （DUV） laser from the sixth harmonic of a 1064nm laser has been firstly used as light source in an ultrahigh energy-resolution angle-resolved photoemission spectroscopy （ARPES）. The wavelength is 177.3nm obtained by using the second harmonic KBe2BO3F2 crystal with a frequency tripled 1064nm Nd：YVO4 laser. The large flux （10^14 - 10^15 photons/s） and narrow line width （0.26 meV） are suitable for the ultrahigh-energy resolution ARPES. The laser-ARPES can be a powerful tool to study the electronic structure at and near the Fermi level of the superconductor and correlated materials. The laser-ARPES has worked more than 500 h already.     

Laser Diode Pumped 1342nm Nd:YVO4 Slab Laser with a Compact Hybrid Resonator

An 880-nm laser-diode stack end-pumped cw 1342nm Nd：YVO4 slab laser with a compact positive confocal unstable-stable hybrid resonator is demonstrated. At absorbed pump power of 115 W, the output power 32.4 W is obtained. The slope efficiency and optical-to-optical conversion efficiency are 42% and 28.2%, respectively. At output power of 22 W, the stable direction M2 is 1.3 and the unstable direction M2 is 1.2.     

Diode-pumped passively Q-switched Nd:LuVO4 laser at 916 nm

We demonstrate a passively Q-switched Nd:LuVO₄ laser at 916 nm by using a Nd, Cr:YAG crystal as the saturable absorber. As we know, it is the first time to realize the laser with a simple linear resonator. When the incident pump power increased from 14.6 W to 23.7 W, the pulse width of the Q-switched laser decreased from 24 ns to 21 ns. The pulse width was insensitive to the incident pump power in the experiment. The average output power of 288 mW with repetition rate of 39 kHz was obtained at an incident pump power of 22.5 W, with the optical-to-optical efficiency and slope efficiency 1.3% and 3.6%, respectively.     

Diode-pumped passively mode-locked Nd:GdVO4 laser at 912 nm

We have demonstrated the stable mode-locked Nd:GdVO₄ laser operating on the ⁴F_3/2-⁴I_9/2 transition at 912 nm. With a four-mirror-folded cavity and a semiconductor saturable absorber mirror for passive mode-locking, we have gained 6.5 ps laser pulses at a repetition rate of 178 MHz. The laser is diode-end-pumped, and the total output power from the out coupler is 128 mw at an incident pump power of 19.7 W.     

Laser Performance of Nd：GGG Operating at 938 nm

We report an efficient diode-pumped Nd-doped Gadolinium gailium garnet （GGG） continuous-wave （CW） laser operating at 938nm. Laser action of 1.6at.% Nd-doped GGG crystais with different lengths and temperatures are aiso investigated. The maximum output power of 620mW is obtained at the incident pump power of 5.0 W with a slope efficiency of 15%.     

Efficient Laser-Diode End-Pumped Passively Q-Switched Mode-Locked Yb：LYSO Laser Based on SESAM

We report an efficient Q-switched laser action based on a semiconductor saturable absorber mirrors （SESAMs） as passively Q-switched laser starter and a Yb：LYSO alloyed crystal as gain material pumped directly by 974nm InGaAs laser diodes. The output pulse duration is measured to be about 7μs, while the average power and the repetition rate of the pulse chain are about 0.92 W and 6.2 kHz, respectively, under 12.5 W absorbed pumping power. The Q-switched mode-locked pulse train is also observed in this setup. The laser performance shows that Yb：LYSO is a promising laser gain medium for laser-diode pumped compact solid-state lasers.     

High-power continuous-wave diode-end-pumped intracavity-frequency-doubled Nd:GdVO4/LBO red laser

A high-power continuous-wave (CW) diode-end-pumped intracavity-frequency-doubled red laser is reported here. The laser consists of a 0.3 at.% Nd:GdVO₄ crystal as laser gain medium, a type II non-critical phase-matched (NCPM) LBO crystal or a type I critical phase-matched (CPM) LBO crystal as frequency-doubler, and a three-mirror-folded cavity. At incident pump power of about 41 W, maximum output powers of 3.8 W and 3 W at 671 nm are obtained with corresponding optical-to-optical conversion efficiency of 9.3% and 7.5%, respectively. During half an hour, the instability of the red beam is less than 3% at output of 3 W.     

A Mid-IR 14.1W ZnGeP2 Optical Parametric Oscillator Pumped by a Tm,Ho:GdVO4 Laser

We report a high power and high efficiency double resonant ZnGeP2 （ZGP） optical parametric oscillator （OPO） pumped by a Tm,Ho：GdVO4 laser. We employ a Tm,Ho：GdVO4 laser as the pump source operated at 2.049 μm with M^2 = 1.1. The ZGP OPO can generate a total combined output power of 14.1 W at 3.80μm signal and 4.45 μm idler under pumping power of 28. 7 W. The slope efficiency reaches 61.8%, and M^2 = 3.6 for OPO output is obtained.     

High Efficient Continuous-Wave Ho：Y/kG Laser Pumped by a Diode-pumped Tm：YLF Laser at Room Temperature

DUAN Xiao-Ming, YAO Bao-Quan, ZHANG Yun-Jun, SONG Cheng-Wei, GAO Jing, JU You-Lun, WANG Yue-Zhu（ National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150001）     

High-power 888-nm-pumped Nd:YVO4 1342-nm oscillator operating in the TEM00 mode

We report on a high-power 888-nm-pumped continuous-wave Nd:YVO₄ laser at 1342 nm. An output power of 24 W emitted into a diffraction limited beam with an M ² parameter better than <1.1 is demonstrated. At an absorbed pump power of 84 W the optical conversion efficiency is 29%.     

Compact, Low Threshold Nd^3＋：YVO4 Self-Raman Laser at 1178 nm

A compact low-threshold Raman laser at 1178 nm is experimentally realized by using a diode-end-pumped actively Q-switched Nd^3＋ ：YVO4 self-Raman laser. The threshold is 370mW at a pulse repetition frequency of S kHz. The maximum Raman laser output is 182 m W with the pulse duration smaller than 20 ns at a pulse repetition frequency of 30kHz with 1.8 W incident power. The optical efficiency from the incident power to the Raman laser is 10% and the slope efficiency is 13.5%.     

High efficiency TEM00 mode, diode-pumped, conduction-cooled, Nd:YAG zig-zag slab laser

We report a compact, conduction-cooled, highly efficient, continuous wave (CW) Nd:YAG slab laser in diode-side-pumped geometry. To achieve high efficiency, a novel laser head for Nd:YAG slab has been developed. For an absorbed pump power of 27.6 W, maximum output power of 10.4 W in multimode and 8.2 W in near-diffraction-limited beam quality has been obtained. Slope and optical-to-optical conversion efficiencies are 45.3% and 37.7% in multimode with beam quality factors (M²) in x and y directions equal to 32 and 8, respectively. TEM₀₀ mode operation was achieved in a hybrid resonator with slope and optical-to-optical conversion efficiencies of 43.2% and 29.7%, respectively. Beam quality factors in x and y directions are ?1.5 and ?1.6 for the whole output power range. The laser radiation was linearly polarized and polarization contrast ratios are >1200:1 in the multimode and 1800:1 in the TEM₀₀ mode operation. In passive Q-switching with Cr⁴⁺:YAG crystal of 68% initial transmission, 18 ns pulsewidth has been achieved with an average power of 2 W at a repetition rate of 16 kHz.     

A Single-Longitudinal-Mode Dual-Wavelength cw Tm,Ho:GdVO4 Microchip Laser

A liquid nitrogen cooled dual-wavelength Tm,Ho：GdVO4 microchip laser is reported. The output dual wavelengths axe at 2038.9nm and 2050.1 nm. At each wavelength, the laser has a single longitudinal mode. The threshold power is nearly 20mW and the slope efficiency is 18.7%. The single longitudinal mode output power reaches 98mW, and the ratio of power is about 60% （2038.9nm） and 40% （2050.1 nm）.