Deuterated potassium dihydrogen phosphate damage performance at 351 nm is studied on a large-aperture laser system. Bulk and rear-surface damage are initiated under the 3ω fluences of 6.T J/cm2 and 33/cm2, and show d...Deuterated potassium dihydrogen phosphate damage performance at 351 nm is studied on a large-aperture laser system. Bulk and rear-surface damage are initiated under the 3ω fluences of 6.T J/cm2 and 33/cm2, and show different growth characteristics under multiple laser irradiations with the fluence of 6 J/cm2. The size and number of bulk damage keep unchanged once initiated. However, surface damage size also does not grow, while surface damage number increases linearly with laser shots. Different damage thresholds and growth behaviors suggest different formations of bulk and surface damage precursors. The cause of surface damage is supposed to be near-surface absorbing particles buried under the sol-gel coating.展开更多
We report the experimental investigation of a stimulated rotational Raman scattering effect in long air paths on SG-III TIL,with a 1053 nm,20-cm-diameter,linearly polarized,3 ns flat-topped laser pulse.An intense spec...We report the experimental investigation of a stimulated rotational Raman scattering effect in long air paths on SG-III TIL,with a 1053 nm,20-cm-diameter,linearly polarized,3 ns flat-topped laser pulse.An intense speckle pattern of near field with thickly dotted hot spots is observed at the end of propagation with an intensity-length product above 17 TW/cm.The Stokes developing from the scattering of the laser beam by quantum fluctuations is characterized by a combination of high spatial frequency components.The observed speckle pattern with small-diameter hot spots results from the combination of the nonlinear Raman amplification and the linear diffraction propagation effect of the Stokes with a noise pattern arising from the spontaneous Raman scattering.A new promising suppression concept based on the special characteristic of the Stokes,called active and selective filtering of Stokes,is proposed.展开更多
The influence of laser beam size on laser-induced damage performance, especially damage probability and the laser-induced damage threshold （LIDT）, is investigated. It is found that damage probability is dependent on...The influence of laser beam size on laser-induced damage performance, especially damage probability and the laser-induced damage threshold （LIDT）, is investigated. It is found that damage probability is dependent on beam size when various damage precursors with different potential behaviors are involved. This causes the damage probability and the LIDT to be different between cases under a large-apertnre beam and a small-aperture beam. Moreover, the fluenee fluctuation of the large-aperture laser beam brings out hot spots, which move randomly across the beam from shot to shot. Thus this leads the most probable maximum fluenee after many shots at any location on the optical component to be several times the average beam fluence, These two effects result in the difference in the damage performance of the optical component between the cases under a large-aperture and small-aperture laser.展开更多
A 2ω wedge design is proposed with KDP crystal to disperse the unconverted light away from the target in a high power laser facility for inertial confinement fusion. The ultraviolet B-integral problem is released, an...A 2ω wedge design is proposed with KDP crystal to disperse the unconverted light away from the target in a high power laser facility for inertial confinement fusion. The ultraviolet B-integral problem is released, and about 1.2 times in color separation angle is achieved according to both theoretical and experimental investigations when compared with conventional 3ω wedge. The frequency conversion etgciency is unaffected when the wedge is along the non-sensitive axis of the tripler.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61505187
文摘Deuterated potassium dihydrogen phosphate damage performance at 351 nm is studied on a large-aperture laser system. Bulk and rear-surface damage are initiated under the 3ω fluences of 6.T J/cm2 and 33/cm2, and show different growth characteristics under multiple laser irradiations with the fluence of 6 J/cm2. The size and number of bulk damage keep unchanged once initiated. However, surface damage size also does not grow, while surface damage number increases linearly with laser shots. Different damage thresholds and growth behaviors suggest different formations of bulk and surface damage precursors. The cause of surface damage is supposed to be near-surface absorbing particles buried under the sol-gel coating.
文摘We report the experimental investigation of a stimulated rotational Raman scattering effect in long air paths on SG-III TIL,with a 1053 nm,20-cm-diameter,linearly polarized,3 ns flat-topped laser pulse.An intense speckle pattern of near field with thickly dotted hot spots is observed at the end of propagation with an intensity-length product above 17 TW/cm.The Stokes developing from the scattering of the laser beam by quantum fluctuations is characterized by a combination of high spatial frequency components.The observed speckle pattern with small-diameter hot spots results from the combination of the nonlinear Raman amplification and the linear diffraction propagation effect of the Stokes with a noise pattern arising from the spontaneous Raman scattering.A new promising suppression concept based on the special characteristic of the Stokes,called active and selective filtering of Stokes,is proposed.
文摘The influence of laser beam size on laser-induced damage performance, especially damage probability and the laser-induced damage threshold （LIDT）, is investigated. It is found that damage probability is dependent on beam size when various damage precursors with different potential behaviors are involved. This causes the damage probability and the LIDT to be different between cases under a large-apertnre beam and a small-aperture beam. Moreover, the fluenee fluctuation of the large-aperture laser beam brings out hot spots, which move randomly across the beam from shot to shot. Thus this leads the most probable maximum fluenee after many shots at any location on the optical component to be several times the average beam fluence, These two effects result in the difference in the damage performance of the optical component between the cases under a large-aperture and small-aperture laser.
文摘A 2ω wedge design is proposed with KDP crystal to disperse the unconverted light away from the target in a high power laser facility for inertial confinement fusion. The ultraviolet B-integral problem is released, and about 1.2 times in color separation angle is achieved according to both theoretical and experimental investigations when compared with conventional 3ω wedge. The frequency conversion etgciency is unaffected when the wedge is along the non-sensitive axis of the tripler.
