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受激布里渊散射(SBS)系统中,具有一定带宽的抽运激光中会含有一定比例的Stokes散射光成分,此Stokes散射光成分经SBS介质后表面反射后,将形成种子光与抽运光联合入射,构成自种子光式SBS放大器.通过数值求解此SBS放大器型耦合波方程组,探讨了抽运光脉冲中所含Stokes散射光成分的比例、抽运激光波长、抽运光能量大小、入射的聚焦高斯光脉冲脉宽、相互作用时间等激光参数对SBS特征参数(Stokes散射光脉冲波形、材料内部最大应力的时间演化及空间分布、脉宽压缩效果、能量提取效率及Stokes散射光的共轭保真度)的影响.同时发现,SBS过程中产生的超声应力不仅会对SBS介质前表面造成破坏,还可能对焦点附近造成破坏;调整各激光参数还会使焦点附近优于前表面先破坏.数值模拟中采用的抽运光是聚焦高斯光束.
关键词:
受激布里渊散射
斯托克斯散射光
冲击应力
能量反射率 相似文献
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A laser dazzling experiment is performed on a linear CCD camera, in which a new dazzling phenomenon is found. It is that a laser beam has caused three spots in the output video of the CCD. The three spots lie in the line along which the linear camera is scanning. The middle spot is the image of laser beam that can be anticipated, but the two sideward spots is a new phenomenon that hasn’t reported in other open literatures. We testify that it isn’t laser high-order mode, diffraction and multiple reflections in the optical path outside the camera that cause the three spots. In the process that linear CCD camera scans the laser beam, the multiple reflections between the lens and CCD image sensor are analyzed. The results indicate that multiple reflections inside the camera can induce the sideward spots. Three basic factors that caused sideward spots have been summed up as follows: the scanning mode of the linear camera, the high brightness of laser, and structure of lens and CCD image sensor. 相似文献
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用波长为1 064 nm、脉宽为5 ms的激光辐照SONY ICX055BL可见光硅CCD器件,实验中由图像采集卡采集得到相机的视频输出,同时用示波器检测ICX055BL的输出信号和垂直输出时钟信号。结果表明,在脉冲激光的辐照下,器件比较容易被破坏。研究中将器件作为一个功能整体,破坏机理分析不只局限于CCD的探测、电荷存储、电荷转移的MOS结构部分。结合实验结果和CCD器件的电路特点,初步判断该器件的破坏机理为电路破坏,脉冲激光所产生的信号电荷冲坏了复位的场效应管,使器件整体永久失效。 相似文献
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采用波长为1.064, 0.532 μm的聚焦高斯光束作为泵浦光,数值求解受激布里渊散射(Stimulated Brillouin Scattering, SBS)放大器型耦合波方程组,比较K9玻璃、熔石英、BK7玻璃、CaF2的SBS特征参数。研究发现:对于相同的激光参数,不同的介质具有不同的SBS特征,声子寿命长则破坏阈值低,破坏效果明显。SBS过程对CaF2的破坏效果较明显,导致了介质前表面的破坏,在一定的激光参数和聚焦参数下,焦点附近优先于前表面破坏。SBS过程可以得到脉宽压缩比大于10、强度比泵浦光峰值高5倍以上的Stokes散射光脉冲。相同激光参数下,不同材料压缩效果及散射光相位共轭保真度不同,CaF2在低泵浦能量时脉宽压缩特性较好;高泵浦能量时,相位共轭保真度较好。固体透明光学材料中可获得大于95%的能量提取效率。 相似文献
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Tian Jiang Xiang-ai Chengi Li Li Hou-man Jiang Qi-sheng Lu 《Optics and Spectroscopy》2011,111(2):162-165
A spectral unrelated laser was induced on the short wave and medium wave photovoltaic HgCdTe infrared detectors respectively, under various power density, the detectors had a serious of output. The results show that the two detectors all had response of spectral unrelated laser, but the response was in the opposite direction. Through the analysis of experimental phenomena, it is found that carrier concentration of detectors before laser irradiation is the reason why the response of detectors was in the opposite direction. It showed valuable clue for future research on photovoltaic HgCdTe irradiated by spectral unrelated laser. 相似文献
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采用800 nm,100 fs的超短脉冲激光器对硅面阵CCD进行辐照实验,观测到饱和、串扰以及永久性损伤等多种可能造成成像器件失效的现象,特别是在激光能量较高时,发现CCD在成像时出现了黑白屏的现象。在飞秒激光器以1,10和1 000 Hz工作的条件下,分别测量了硅面阵CCD的饱和阈值、串扰阈值和破坏阈值。对破坏后的CCD器件进行了显微分析。在1 kHz工作的条件下进行了视场外干扰实验,观察到串扰和全屏饱和的现象。 相似文献