All solid-state passively Q-switched frequency-doubled intra-cavity Nd: GdVO4/KTP laser

In this paper, laser frequency-double and passive Q-switching are studied. The optimum coupling at endpump and optimum design of resonator are also investigated. The maximum output power of TEM00 is 1.68 W at 1.06-μm wavelength. Optic-optic conversion efficiency is 48.6%, and the slope efficiency is 56.3%. The maximum output of green light is 0.235 W. The smallest pulse-width of green light is 27.42 ns, optic-optic conversion efficiency of green light is 7%, and beam quality factor M2 ＜ 1.2. Thermal lens effect is discussed.     

Continuous-wave green laser of 34 W by intracavity frequency doubling in diode-side-pumped Nd:YAG/KTP

Continuous-wave green laser with a maximum power of 34 W has been obtained by intracavity frequency doubling with KTP in diode-side-pumped Nd：YAG. The Nd：YAG/KTP green laser has a simple three- mirror V-fold cavity structure. The optical-to-optical conversion efficiency is 9.5%. The instability of the laser is measured when the output powers are near 16, 21, 30, and 34 W after the beam is filtered. At the maximum output power, the M^2 factor is measured to be 8.     

All-Solid-State Near-Infrared and Blue Femtosecond Laser System

We investigate an all-solid-state continuous wave(cw) green (532nm),femtosecond near-infrared (823.1nm) and blue (402nm) laser system which is pumped by a diode-laser-pumped intracavity frequency-doubled and all-self-structuring cw Nd:YVO4/KTP 532nm green laser.The cavity parameters of the Nd:YVO4/KTP laser have been optimized and the maximum 5.6W TEM00 green laser is obtained at a 22W pump power with an optical-optical conversion efficiency of 25.5%.A Ti:Sapphire laser and nonlinear second-harmonic generation by a crystal BBO is used to obtain different wavelengths.A femtosecond laser with an average output power of 300mW at 823.1nm and 73mW at 402nm is obtained when the green pump power is 2.5W.The spectral full width at half maximum are 32.3 nm and 5.1 nm,which can sustain the pulses of 22 fs and 33.3 fs,respectively.     

High peak power 1.0 μm and tri-wavelength 1.3 μm Nd:ScYSiO_5 crystal lasers

With a Nd:ScYSiO_5 crystal, a high peak power electro-optically Q-switched 1.0 μm laser and tri-wavelength laser operations at the 1.3 μm band are both investigated. With a rubidium titanyle phosphate(RTP) electro-optical switcher and a polarization beam splitter, a high signal-to-noise ratio 1.0 μm laser is obtained, generating a shortest pulse width of 30 ns, a highest pulse energy of 0.765 mJ, and a maximum peak power of 25.5 kW,respectively. The laser mode at the highest laser energy level is the TEM200 mode with the Mvalue in the X and Y directions to be M_x~2= 1.52 and M_y~2= 1.54. A tri-wavelength Nd:ScYSiO_5 crystal laser at 1.3 μm is also investigated. A maximum tri-wavelength output power is 1.03 W under the absorbed pump power of7 W, corresponding to a slope efficiency of 14.8%. The properties of the output wavelength are fully studied under different absorbed pump power.     

A Diode-Stack End-Pumped Electro-Optically Q-Switched Nd:YAG Slab Oscillator--Amplifier System

A laser diode-stack end-pumped electro-optically Q-switched Nd：YAG slab oscillator-amplifier system with neardiffraction-limited output is demonstrated by a stable-unstable hybrid resonator. The average power of 100 W at a repetition rate of lOkHz with a pulse width 14.7ns and average power of 76.3 W at a repetition rate of 5kHz with a pulse width of 10.2ns are measured. At the repetition rate of 10 kHz and at an output power of 89 W, the beam quality factors M^2 in the unstable and stable directions are 1.3 and 1.5, respectively.     

LD-pumped 6 W cw Tm^3＋-Doped Silica Double-Cladding Fibre Laser

We report a thulium-doped silica fibre laser that generates a maximum cw output power of 6 W in a 2 μm wavelength range when cladding-pumped by a laser diode （LD） operating at approximately 791 nm at room temperature. The slope efficiency with respect to the launched pump power is 50% and 38.4%, with and without an output coupler mirror, respectively. The corresponding thresholds are 2.8 W and 4.8 W, respectively. The beam qualities Mx^2 and My^2 are 1.26 and 1.32, respectively. The experimental results are also analysed.     

Stable High Power and High Beam Quality Diode-Side-Pumped Continuous-Wave Intracavity Frequency-Doubled Nd:YAG Laser

We report a stable high power and high beam quality diode-side-pumped cw green laser from intracavity frequency-doubled Nd： YAG laser with KTP. By using a L-shaped concave-convex resonator, designed with two Nd：YAG rods birefringence compensation, a large fundamental mode size in the laser crystal and a tight focus in the nonlinear crystal could be obtained simultaneously. The green laser delivers a maximum 532nm output power of 23.2 W. Under 532nm output power of 20.9 W, the beam quality factor is measured to be 4.1, and the fluctuation of the output power is less than 1.4% in an hour.     

A high-power high-stability Q-switched green laser with intracavity frequency doubling using a diode-pumped composite ceramic Nd：YAG laser

We successfully obtain a high-average-power high-stability Q-switched green laser based on diode-side-pumped composite ceramic Nd:YAG in a straight plano-concave cavity. The temperature distribution in composite ceramic Nd:YAG crystal is numerically analyzed and compared with that of conventional Nd:YAG crystal. By using a composite ceramic Nd:YAG rod and a type-II high gray track resistance KTP (HGTR-KTP) crystal, a green laser with an average output power of 165 W is obtained at a repetition rate of 25 kHz, with a diode-to-green optical conversion of 14.68%, and a pulse width of 162 ns. To the best of our knowledge, both the output power and optical-to-optical efficiency are the highest values for green laser systems with intracavity frequency doubling of this novel composite ceramic Nd:YAG laser to date. The power fluctuation at around 160 W is lower than 0.3% in 2.5 hours.     

589-nm yellow laser generation by intra-cavity sum-frequency mixing in a T-shaped Nd:YAG laser cavity

To obtain high power 589-nm yellow laser, a T-shaped thermal-insensitive cavity is designed. The optimal power ratio of 1064- and 1319-nm beams is considered and the fundamental spot size distribution from the output mirror to the two laser rods are calculated and simulated, respectively. As a result, a 589-nm yellow laser with the average output power of 5.7 W is obtained in the experiment when the total pumping power is 695 W. The optical-to-optical conversion efficiency from the fundamental waves to the sum frequency generation is about 15.2% and the pulse width is 150 ns at the repetition rate of 18 kHz. The instability of the yellow laser is also measured, which is less than 2% within 3 h. The beam quality factors are Mx^2 = 4.96 and My^2 = 5.08.     

A 4.8-W M^2 = 4.6 Continuous-Wave Intracavity Sum-Frequency Diode-Pumped Solid-State Yellow Laser

A yellow continuous wave with beam quality M^2= 4.6 and output power of 4.8 W at 589nm is generated by intracavity sum-frequency mixing of 1064 nm and 1319 nm radiations of a Nd：YAG laser. To achieve high beam quality at high power, thermally near-unstable flat-flat resonators with two-rod birefringence compensation are designed to obtain the large fundamental mode size inside the Nd：YAG rods and the same beam width inside the KTP crystal. The optimal intracavity power ratio of both 1064nm and 1319nm beams is also considered. The output power fluctuation of the yellow laser remains less than 5% in four hours.