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A compact optically pumped vertical-external-cavity surface-emitting-semiconductor laser (OP-VECSEL) at 1178 nm for μs pulsed operation is reported for the first time. The laser employed a V-shaped resonator with the cavity length of 300 mm, pumped by a 200 μs pulse 808 nm laser operating at a repetition rate of 1 kHz. The maximum output power about 0.78W was obtained at pump power of ~5.9 W. The corresponding conversion efficiency from absorbed pump power to 1178 nm was 13.2%. Further, by the intra-cavity frequency doubling of the VECSEL, a μs pulsed 589 nm laser has broad prospects in the application of sodium guide stars.

Picosecond (ps) mid-infrared optical parametric amplification pumped at 1064nm was investigated in experiment. The high energy ps laser generation in 2-12μm wavelength region based on KTP, KTA, MgO:PPLN and BGSe crystals was demonstrated

In order to decrease the development costs, shorten the developing cycle, improve the overall performance and reduce the environmental pollution of the wafer precision grinding machine, the structure, transmission, movement of grinding system for wafer precision grinding machine is analyzed based on mechanical system mechanics, the three-dimensional model of the grinding system is established, based on frame animation technology and via secondary development of Pro/E in the environment of VS 2008, the virtual prototype of grinding system for wafer precision grinding machine is developed, the kinematics and dynamics simulation of the grinding system is realized.

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%.

Output power of 1.1 W and linewidth of 0.7 GHz and beam quality of M2 = 1.2 yellow beam was generated by sum-frequency mixing 1064 nm and 1319 nm radiations of quasi-continuous-wave diode-pumped Nd:YAG lasers inside a pair of KTP crystals. The narrow linewidth 1064 nm and 1319 nm beams were realized by inserting solid etalons in the three-mirrors ring resonators. The wavelength of yellow laser was adjusted and controlled by the control of etalon angle and temperature. To achieve the high beam quality at the average power, thermally near-unstable resonators with two-rod birefringence compensation were designed and employed in the 1064 nm and 1319 nm ring lasers. The high sum-frequency efficiency was obtained by using a pair of KTP crystals with a walk-off-compensated configuration. The power of the diffraction-limited, narrow linewidth and precise-tunability yellow laser was reached to 1.1 W by mixing the 1064 nm beam of 7.5 W and the 1319 nm beam of 3.2 W.

This paper presents two extensions to inverse displacement mapping, methods which attempt to render effects offered by displacement mapping, motion parallax, self-occlusion, self-shadowing and silhouette, without actually perturbing the surface geometry. The first extension, Normal-Based Curved Silhouette (NCS), allows better rendering for object's silhouette. At each step of intersection finding, NCS continuously bends the viewing ray according to the current local tangent space associated with the surface. Thus, it allows mapping a displacement map onto an arbitrary curved surface with more accurate silhouette. For the second extension, we propose a hierarchical adaptive preprocessing method that is around 10 times faster than conventional methods, allowing our space leaping approach to be used for rendering dynamic displacement maps. In addition, we propose an extension to cone step mapping. The extension, Anisotropic Cone Mapping (ACM), provides a more efficient and accurate way for calculating intersections. Anisotropic cones are used as the bounding volume for the empty space above texels, allowing faster convergence and rendering speed. Both proposed methods are suited for many realtime 3D applications because of their low memory cost and good performance in both rendering quality and speed.

This paper investigates the scattering effect of domestic 0.5 at % ceramic Nd:YAG. An effective method has been utilized to measure the scattering and absorption coefficients. An end-pumped continuous wave (CW) Nd:YAG ceramic laser was also demonstrated. A maximum output power of 6.7 W at 1064 nm was obtained at an 808-nm pump power of 32.9 W. Conversion efficiency and slope efficiency have been achieved. This indicates that scattering has an important effect on the optical performance of ceramic Nd:YAG.

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.

We report a Q-switched 2-μm Tm:YAG laser based on intracavity-pumped by a 1064-nm Nd:YAG laser operating at room temperature for the first time. An average output power of 5.1 W is obtained with the repetition rate of 30 kHz and a pulse width of 300 ns. In addition, we demonstrate a 12.5-W continuous-wave 2-μm Tm:YAG laser, which is, to our best knowledge, the highest power for intracavity-pumping configuration.

A high-efficiency high-power Nd:YAG laser under 885nm laser diode (LD) pumping is demonstrated. The laser crystal is carefully designed, and the overlapping between the pump modes and the laser modes is optimized. The maximum output power at 1064 nm is 87W under the absorbed pump power 127.7W, corresponding to a slope efficiency of 72.4% and an optical-optical efficiency of 68.1%. The optical-optical efficiency is 58.4% for the pump power emitted directly from the LD. To our best knowledge, this is the maximal optical-optical conversion efficiency obtained for the LD end-pumped Nd:YAG lasers so far.

Laser performance of 1064 nm domestic Nd:YAG ceramic lasers for 885 nm direct pumping and 808 nm traditional pumping are compared. Higher slope efficiency of 34% and maximum output power of 16.5 W are obtained for the 885 nm pump with a 6 mm length 1 at.% Nd:YAG ceramic. The advantages for 885 nm direct pumping are discussed in detail. This pumping scheme for highly doping a Nd:YAG ceramic laser is considered as an available way to generate high power and good beam quality simultaneously.

The saturation of stimulated Raman scattering (SRS) through Langmuir decay instability (LDI) and electron trapping in laser-plasma interaction process is studied. Analytical expressions for the saturation time of SRS are obtained for both the LDI and electron trapping schemes in 1-D homogeneous plasma irradiated by unrelativistic laser beams. The simple analytical model agrees well with numerical simulation and experiment in respect of the dependence of the saturation time of SRS on the parameters of lasers and plasmas.

This paper reports a high-power all-solid-state yellow laser based on intracavity KTP crystal sum-frequency generation. In order to achieve high output power，three key techniques are used：Firstly，the system is designed to operate in a pulsed mode to increase the beam quality and optical-to-optical conversion efficiency under the same pump level. Secondly，thermal near-unstable resonator design and two-rod birefringence compensation is used to acquire large fundamental mode size in Nd：YAG rod. Thirdly，by optimizing an L-shaped co-folding-arm plane-concave symmetrical cavity，the two fundamentals have a high spatial overlap in the sum-frequency crystal and satisfy the power ratio requirement. As a result of the applications of these techniques，a quasi-continuous-wave yellow laser with output power of 7.6W and repitition frequency of 1.1kHz is obtained. To the best of our knowledge，this is the highest yellow laser output power produced by an intracavity sum-frequency Nd：YAG laser.