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%.     

Passively mode-locked grown-together composite YVO4 /Nd:YVO4 crystal laser with a semiconductor saturable absorber mirror under 880-nm direct pumping

A passively mode-locked grown-together composite YVO 4 /Nd:YVO 4 crystal laser is demonstrated with a semiconductor saturable absorber mirror by 880-nm laser-diode direct pumping.Under the absorbed pump power of 24.9 W,a maximum output power of 10.5 W at the repetition rate of 77 MHz is obtained,corresponding to the optical-optical conversion efficiency of 42.1% and the slope efficiency of 53.4%.The pulse width measured is 33 ps at the output power of 10 W.     

High Power Diode-End-Pumped Nd：YAG 946-nm Laser and Its Efficient Frequency Doubling

We report a high power operation of the ^4Fa/2 → ^4I9/2 transition in diode-end-pumped laser at 946nm. The maximum output of 5.1 W is obtained with a short linear plano-concave cavity, and the slope efficiency is 24.5% at incident pump power of 23.3 W. To our knowledge, this is the highest value of the LD-pumped Nd:YAG 946 nm lasers that employ the conversional Nd:YAG rod as the gain medium. By intracavity frequency doubling with an LBO crystal, up to 982mW cw output power in the blue spectral range at 473nm is achieved at an incident pump power of 10.9 W with a compact three-element cavity, leading to optical-to-optical conversion efficiency of 9%. The conversion efficiency should be increased to 15.1%, if the rather low absorption coefficient of this Nd:YAG is considered.     

A Stable Diffusion-Bonded Tm：YLF Bulk Laser with High Power Output at a Wavelength of 1889.5 nm

A high power diode-pumped diffusion-bonded Tm：YLF laser operating at 1889.5nm with a FWHM linewidth of less than 0.1 nm is reported. A Brewster plate and two Fabry-Perot etalons are inserted in the laser cavity for spectral narrowing and stabilization. Under an incident pump power of 136.8 W, 46.1 W of output power is achieved, corresponding to an optical-to-optical conversion efficiency of 33.7% and a slope efficiency of 42.8%. The laser wavelength shift of only 0.07nm with the incident pump power from 20.1 W to 136.8W is observed. The M2 factor at maximum output power is calculated to be 2.3 in the x-axis and 2.0 in the y-axis, respectively.     

High-power continuous-wave and high-energy Q-switched miniature Yb:Y_3Ga_5O_(12) crystal lasers

We report on the continuous-wave(CW) and passive Q-switching performance of a miniature Yb:Y_3Ga_5O_(12)crystal laser end pumped by a 935-nm diode laser. A maximum CW output power of 12.03 W is produced with an optical-to-optical efficiency of 54.4%, while the slope efficiency is 63%. In the passively Q-switched operation achieved with a Cr~(4+):YAG saturable absorber, an average output power of 2.12 W at 1025.2 nm is generated with a slope efficiency of 46% at a pulse repetition rate of 5.0 kHz. The pulse's energy, duration, and peak power are 424 μJ, 2.3 ns, and 184.3 k W, respectively.     

A Laser-Diode End-Pumped Nd:YVO4 Slab Laser at 1342nm

A laser-diode end-pumped Nd：YVO4 slab laser with a fiat-concave stable cavity at 1342nm is demonstrated. Under the pumping power of 92 W, a cw laser of output 17.8 W is obtained with the slope efficiency of 25.6%.     

A Diode-Pumped 1617 nm Single Longitudinal Mode Er：YAG Laser with Intra-Cavity Etalons

We demonstrate the continuous wave p-polarized single longitudinal mode （SLM） operation of an Er：YAG laser at 1617.6nm pumped by a diode-laser with three inserted Fabry-Perot （FP） etalons at room temperature. The Brewster angle inserted FP is applied to obtain the p-polarized laser. For free running, the maximum output power is 570 m W with a pump power of 12.5 W. An incident pump power of 12.5 W is used to generate the maximum p-polarized single longitudinal mode output power of 78.5 m W, corresponding to a slope efficiency of 1.6% and an optical-to-optical efficiency of 0.61%. The beam quality M2 is measured to be 1.15 at the highest SLM output power. This stable polarized SLM oscillation is encouraging due to its application for an injection-locked system used as a master laser.     

Watt-level Yb-doped silica glass fiber laser with a core made by sol-gel method

A Yb-doped silica glass fiber laser with a core made by sol-gel method is reported. The maximum power of 1.14 W is obtained with a pump power of 5.46 W at a wavelength of 976 nm. The slope efficiency is 34%. The refractive index fluctuation across the core is below 5×10^-4 at a doping level of Yb 0.15 mol%, A203 4.0 mol%, and P2O5 2.0 mol%. High background attenuation of 6 dB/m at 1 053 nm limites the slope efficiency and maximum output power.     

High Efficiency Continuous-Wave Tm：Ho：GdVO4 Laser Pumped by a Diode

We report a high efficiency cw diode-pumped cryogenic Tin(Sat.%), Ho(0.5at.%):GdV04 laser. The pumping source is a fibre-coupled laser diode with fibre core diameter of 0.4 mm and numerical aperture of 0.3, supplying power 14.8 W at 793.6nm. For input pump power of 13.6 W at 794.2nm, the maximum output power of 4.2 W,optical-to-optical conversion efficiency of 31% and slope efficiency 38% have been attained at 2.0485 μm. To our knowledge, the operating performance is the best among the previously reported Tm:Ho:GdVO4 lasers. We also analyse the influence of pump wavelengths (from 792nm to 794.2nm) on the output power, the optical-to-optical conversion efficiency increases with the longer pump wavelength which is closer to the absorption peak of 797nm in Tm,Ho:GdV04.     

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%.     

Wildly Tunable,High-Efficiency MgO：PPLN Mid-IR Optical Parametric Oscillator Pumped by a Yb-Fiber Laser

We demonstrate a wildly tunable, high-eFficiency mid-infrared （mid-IR） output-coupled single resonant optical parametric oscillator （OC-SRO） pumped by a Yb-fiber laser. The compact mid-infrared source employs a 50- mm-long, multi-grating MgO-doped periodically poled lithium niobate （MgO-PPLN） crystal, providing as much as 1.73 W idler power at 3.012#m, and 1.27W signal power at 1645nm, corresponding to an overall conversion efficiency of 41.7% and a slope efficiency of 77.9%. In particular, the mid-infrared output power of 1.03 W and 0.67W are obtained at 3.7μm and 3.9μm, respectively, with an optical-to-optical conversion efficiency of 14.3% and 9.3%. Furthermore, the idler light is tunable from 3 μm to 3.9 μm by changing the periods from 31 to 28.5μm, with the output power 〉1 W over 78% of the tuning range. Our experimental results are pump power limited and further mid-IR power and conversion efficiency could be obtained with a suitable high-power pump source. The total OC-SRO output power rms at 2.6 W is about 0.6% during 2 h measurement.     

Diode-Pumped Passive Q-Switched 946-nm Nd：YAG Laser with 2.1-W Average Output Power

We demonstrate a diode-pumped passive Q-switched 946nm Nd: YAG laser with a diffusion-bonded composite laser rod and a co-doped Nd, Cr:YAG as saturable absorber. The average output power of 2.1 W is generated at an incident pump power of 14.3 W. The peak power of the Q-switched pulse is 643 W with 80kHz repetition rate and 40.8 ns pulse width. The slope efficiency and optical conversion efficiency are 17.6% and 14.7%, respectively.     

Diode-pumped 1018-nm ytterbium-doped double-clad fiber laser

We report a 1 018-nm ytterbium-doped double-clad fiber laser pumped by 970-nm diode. A pair of fiber Bragg gratings with reflectivities of 99.9% and 9% at a center wavelength of 1 018.9 nm are employed as cavity mirrors. The ytterbium-doped double-clad fiber is a 2.6-m-long Liekki fiber. Laser output power of 7.5 W at 1 018 nm is obtained under the pump power of 59.2 W. The overall slope efficiency of the fiber laser is about 16%. This low slope efficiency is mainly due to the incomplete absorption of the pump power.     

Low Threshold and High Conversion Efficiency Nanosecond Mid-Infrared KTA OPO

Based on a Type II non-critically phase-matched KTA crystal, a low-threshold and high conversion efficiency mid-infrared optical parametric oscillator （OPO） pumped by a diode-end-pumped Nd：YVO4 laser is demonstrated. The OPO threshold is only 0.825W. The maximum output power of 435mW at 3.47μm is achieved with the repetition rate of 30kHz, corresponding to an optical-to-optical conversion efficiency of 4.4%. The photon conversion efficiency is as high as about 64%. The pulse width is 3.5ns with a peak power of 4kW for the maximum output power.     

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.     

Large-aperture end-pumped Nd：YAG thin-disk laser directly cooled by liquid

A large-aperture Nd:YAG thin-disk laser directly cooled by liquid is end-pumped by two spatial selforganized laser diode arrays. The pump coupling efficiency reaches as high as 93%. Without any complex pump coupling components, the structure becomes simplified and compact. By optimizing the incident angle of the pump beam, a pump power density of 578 W/cm2 is achieved with a pump uniformity of 5.52%. Up to 1 346-W peak output power with a slope efficiency of 54.9% is obtained when pumping with a long pulse. The near-field pattern of the laser output is uniform.     

Diode-pumped vertical external cavity surface emitting laser at 1 μm

We demonstrated a diode-pumped vertical external cavity surface emitting laser with simple plane-concave cavity. When the pump power at a wavelength of 811.6 nm is 1.5 W, the maximum output power is 40.4 mW at the wavelength of 1005.8 nm. The optical-optical conversion efficiency is 2.7%. .     

312 MHz,compact all-normal-dispersion Yb:fiber ring laser with an integrated WDM-ISO

A compact and stable all-normal-dispersion mode-locked ring fiber laser with the repetition rate of 312 MHz is obtained with a wavelength-division multiplexing isolator. The compressed pulse is nearly transform-limited and the pulse width is 118 fs. It exhibits an optical efficiency of 50% and the maximum output power is about 205 m W with a 410 m W pump.     

High-Power Continuous-Wave Diode-End-Pumped Intracavity Frequency Doubled Nd：YVO4 Laser at 671 nm with a Compact Three-Element Cavity

We report a high-power high-efficient continuous-wave （cw） diode-end-pumped Nd：YVO4 1342-nm laser with a short plane-parallel cavity and an efficient cw intracavity frequency-doubled red laser at 671 nm with a compact three-element cavity. At incident pump power of 20.6 W, a maximum output power of 7 W at 1342 nm is obtained with a slope effciency of 37.3%. By inserting a type-Ⅰ critical phase-matched LBO crystal as intracavity frequencydoubler, a cw red output as much as 2.85-W is achieved with an incident pump power of 16.9 W, inducing an optical-to-optical conversion efficiency of 16.9%. To the best of our knowledge, this is the highest output of diodepumped solid-state Nd：YVO4 red laser. During half an hour, the red output is very stable, and the instability of output power is less than 1%.     

Highly efficient cascaded P-doped Raman fiber laser pumped by Nd:YVO4 solid-state laser

A highly efficient cascaded P-doped Raman fiber laser(RFL)pumped by a 1064-nm continuous wave (CW)Nd:YVO_4 solid-state laser is reported.1.15-W CW output power at 1484 nm is obtained while the input pump power is 4 W,corresponding to the power conversion efficiency of 28.8%.The threshold pump power for the second-order Stokes radiation is 1.13 W.The slope efficiency is as high as 42.6%.The experimental results are in good agreement with theoretical ones.Furthermore,the power instability of the P-doped RFL at 1484 nm in an hour is observed to be less than 5%.