Bo Yong

106.5 W high beam quality diode-side-pumped Nd:YAG laser at 1123 nm

We demonstrate a diode-side-pumped continuous wave (CW) Nd:YAG laser at 1123 nm with over 100 Ws output power and good beam quality. The resonator adopts convex-convex structure working in a thermally near unstable cavity. By precise coating design a single 1123 nm wavelength is delivered. Under the pumped power of 870 W, an output power of 106.5 W is obtained, corresponding to an optical-optical conversion efficiency of 12.2%. The beam quality of M(2) factor is measured to be 5.6. To the best of our knowledge, this is the highest output power with good beam quality for 1123 nm CW Nd:YAG laser.

33 W quasi-continuous-wave narrow-band sodium D-2a laser by sum-frequency generation in LBO

We demonstrate an all-solid quasi-continuous-wave (QCW) narrow-band source tunable to sodium D-2a line at 589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal. The 1064 nm and 1319 nm lasers are produced from two diode side-pumped Nd:YAG master oscillator power amplifier (MOPA) laser systems, respectively. A 33 W output of 589 nm laser is obtained with beam quality factor M-2 = 1.25, frequency stability better than +/- 0.2 GHz and linewidth less than 0.44 GHz. A prototype 589 nm laser system is assembled, and a sodium laser guided star has been successfully observed in the field test.

High-average-power third harmonic generation at 355 nm with CsB3O5 crystal

A 17.7 W average power output at 355 nm by the third harmonic generation (THG) of 1064 nm light has been obtained with the nonlinear optical crystal CsB3O5 (CBO). The fundamental light source is a diode-pumped Nd:YAG laser with a pulse duration of 70 ns and a repetition rate of 7 kHz. A CBO crystal cut for type-II PM angles is used in the experiment. The THG energy conversion efficiency with CBO is twice as large as that with LBO. As a THG crystal, CBO has better performance than that of LiB3O5 crystal (LBO).

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 526 W Diode-Pumped Nd:YAG Ceramic Slab Laser

A diode-side-pumped Nd:YAG ceramic slab laser with a high power output is presented. An average power of 526 W is achieved at 1064 nm with a repetition rate of 120 Hz and a pulse width of 180 μs from a 93mm × 52mm × 8 mm ceramic slab at a pump power of 1928 W, corresponding to an optical-to-optical efficiency of 27.3%.

High Efficiency Multi-kW Diode-Side-Pumped Nd:YAG Laser with Reduced Thermal Effect

We demonstrate a high efficiency multi-kW diode-side-pumped Nd:YAG laser. High cooling efficiency of the diode-side-pumped module in the laser is achieved. The middle portion of the Nd:YAG rod in the module is cooled by a coolant jet with screwed side surface, and the end-caps of the rod without screwed side surface are cooled by Au coated on the surface. The thermal effect of the laser rod is reduced, which leads to high output power with high optical-optical conversion efficiency. By using three identical Nd:YAG laser modules, an output power of 4.2 kW and beam quality of 58 mm.mrad with an optical-optical efficiency of 35% at 1064 nm is obtained in a laser oscillator. By using four identical Nd:YAG laser modules, an output power of 3.1 kW and beam quality of 17 mm.mrad with an optical-optical efficiency of 25.8% is demonstrated in a master oscillator power-amplifier system.

A Continuous-Wave Diode-Side-Pumped Tm:YAG Laser with Output 51 W

A compact diode-side-pumped Tm:YAG laser is presented, which can output 51 W of cw power at 2.02μm. The Tm:YAG rod is side pumped by nine diode arrays with the central wavelength of 783nm and the with bandwidth of about 2.5 nm at 25° C. To decrease the thermal effect on the both ends and dissipate the heat effectively, one composite Tm:YAG rod with the undoped YAG end caps and the screw threads on the side surface of the rod is used as the laser crystal. The maximum optical-to-optical conversion efficiency of the 2.02-μm laser output is 14.2%, with a slope efficiency of 26.8%.

High Beam Quality Green Generation with Output 140 W Based on a Thermally-Near-Unstable Flat–Flat Resonator

By using a diode-side-pumped Q-switched Nd:YAG rod laser based on a thermally-near-unstable flat-flat resonator, an intracavity-frequency-doubled green beam generation is investigated. Output power 140 W is obtained at a repetition rate of 10 kHz and a pulse width of 110 ns. The green beam quality factors M-x(2) and M-y(:)2 which are measured by a laser beam analyser, are 10.65 and 10.85, respectively. at output, power of 124 W.

High Power Quasi-Continuous-Wave Diode-End-Pumped Nd:YAG Slab Amplifier at 1319 nm

We report a high power high beam quality quasi-continuous-wave (QCW) diode-end-pumped Nd:YAG slab amplifier at 1319 nm. The strongest 1064 nm parasitic oscillation has been successfully suppressed by reasonable coating design. In a five-pass configuration, the amplifier yields a 42.3 W linearly polarized 1319 nm output at repetition rate of 1 kHz with pulse duration of 75 μs and beam quality factors of Mx2 = 1.13 and My2 = 2.16 in the orthogonal directions. The fluctuation of the amplifier output power is measured to be ±0.6 %. Furthermore, a computational model of QCW pulse amplification is employed to examine the amplification process.

High power high beam quality diode-pumped 1319-nm Nd:YAG oscillator-amplifier laser system

This paper demonstrated a high power and high beam quality diode-pumped 1319-nm Nd:YAG master oscillator-power amplifier laser system. A thermally near-unstable resonator with four-rod birefringence compensation flat-flat cavity was adopted as the master oscillator. A solid etalon was inserted in the unidirectional ring resonator to compress the laser linewidth. Under a repetition rate of 500 Hz and pulse width of 160 μs, the master oscillator delivers an average output power of 16.8 W at 1319 nm with linear polarisation, beam quality factor M2 = 1.16 and linewidth of 3.2 GHz. A double-pass power amplifier with two amplifier stages was employed for higher power scaling and the output power was amplified to be 25.9 W with M2 = 1.43.