激光强度时空分布测量漫散射取样衰减技术研究

Research on scattering sampling and attenuating in measurement of laser intensity distribution

激光强度时空分布的测量对于诊断与评估激光系统的性能具有重要意义,减少激光入射角度影响、对大尺度激光束进行高分辨力、高占空比取样是准确测量激光强度分布的关键,结合漫散射光分布与入射光方向无关的原理,提出了激光强度时空分布测量漫散射取样衰减方法,设计了漫散射取样衰减单元,建立了光强计算模型,推导了光强计算公式并进行了验证,光强衰减倍数实验结果与理论值一致。介绍了漫散射取样衰减装置与光电管阵列或CCD成像系统的组合应用。该方法的优点:空间取样分辨力高,可达2mm左右;使用角度宽,可达±30°而不需要响应修正;占空比高,可达40%以上;衰减倍数范围大,可以通过调节衰减结构参数实现任意需要的衰减倍数。漫散射取样衰减为阵列探测器对大尺寸激光束进行取样和衰减提供了一种新方法,提高了激光强度分布测量能力和测量精度。

The measurement of laser intensity temporal-spatial distribution is of great importance for diagnosing and evaluating the performance of laser system. Spatially sampling large size laser beam is the first step to measure the laser beam parameters, decreasing the influence on measurement result from the laser incident angle and sampling large size laser beam with high spatial resolution and high duty ratio are very critical for accurately measuring laser beam intensity temporal-spatial distribution. Base on the principle of diffuse scattering, which means the distribution of scattering light has nothing to do with incident light, scattering sampling and attenuating method was put forward in array detectors for the measurement of laser intensity distribution. The diffuse scattering principle was briefly introduced. The construction of sampling and attenuating was given, the transmission laser intensity computation model was set up, the intensity formula was deduced and verified through experiments. The applications of scattering sampling unites and photodiode array or CCD were introduced. There are notable advantages, high resolution which is 2 mm or so; high duty ratio which is up to 40%; wide use angle which can be up to 30° and adjustable multiple attenuation which wants. Scattering sampling and attenuating provide a new method for array detector to sample laser beam, which overcome the shortages of technologies available, improves the measuring ability and measuring accuracy significantly and is of great significance to laser intensity distribution measurement device, the method can be widely used to development the measurement systems of laser beam parameters.