In adaptive optical system, the configuration of the sub- apertures of wave-front sensor and deformable mirror actuators will affect the wave-front correcting ability and stability of the system. For annular profile laser beam, six kinds of annular configurations with sub-apertures of wave- front sensor arranged around the annular and a square configuration with square sub-apertures of wave-front sensor are simulated. These configurations are compared each other in the wave-front correcting ability and stability. The optimum configuration for annular beam is selected.
Adaptive optics has been successfully used in astronomy to obtain near diffraction limited images. It also can be used to improve the laser beam quality. In this paper, a test that a He-Ne laser was used to simulate an annular beam and was cleaned up by the 61 elements adaptive optical system is reported. The results show that the beam quality is improved.
In the present paper, the experimental results of a 10 ns, 532 nm Q-switched Nd:YAG laser- induced surface and bulk damage of uncoated, polished Ti:sapphire (Ti:3+:Al2O3) single crystal, grown by the Induction Thermal Field Up-shift Method in our laboratory, are reported. It is found that the measured thresholds of both surface damage and bulk breakdown strongly varied not only with the Ti3+ ion doping concentrations of the tested sample but also with the crystallographic direction of the crystal, whose exact nature has not been previously identified. It is also observed that in the same conditions the surface damage threshold is much lower than the bulk damage threshold. The surface damage is the main cause to laser-induced damage of Ti:sapphire single crystal. In addition, the relative damage morphology and the possible explanation for these experimental results are given.
Titanium-doped Al2O3(Tl3+:Al2O3) single crystals weighing 3 Kg and 120 mm in diameter have been grown by the temperature gradient technique. The crystals used had excellent optical homogeneity, less scattering particles, and low dislocation density.
The YAG:Nd single crystal boules with free-of-scattering centers, weighing 3000 g and 120 mm in diameter have been grown by the temperature gradient technique. The furnace enlarged on the excellent (phi) 80 mm YAG:Nd crystals to achieve such a large-size crystal.
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