大动态范围窄脉冲激光参数测量探头

Narrow pulsed laser probe with high dynamic range

设计了一种双探测器结构的窄脉冲激光参数测量探头,解决了大动态测量范围和高速放大电路高增益时信噪比低的矛盾。通过对探头前端的光学特性进行分析,给出了均匀照射时探头前端的照度传递系数,并且对非均匀照射情况下可能的最大模型误差进行了分析,指出增大漫透射陶瓷片与探测器的距离和减小出光孔径有利于降低模型测量误差,减小双探测器偏离光轴的安装距离有利于提高两个探测器的测量一致性。测试表明,对于10 ns脉宽的1.064μm激光,所研制的探头在50 nJ^8 mJ范围内的测量误差低于±9%,输出激光脉冲波形幅度在0.7~1.4 V之间。利用推导出的照度传递系数公式还测出了漫透射陶瓷片的透过率为0.60,测量误差为±1.7%。

To reduce the high dynamic range requirement on high speed amplifier,a probe for measuring the far field characteristics of narrow pulsed laser was designed based on using double detectors instead of the traditional single detector.From radiometric analysis on the probe＇s optical structure,the illuminance transfer coefficient was deduced when the probe was irradiated evenly,and the model＇s possible maximal error was also investigated when the probe was irradiated unevenly.From the aspect of minimizing the model＇s error,both increasing the distance between translucent ceramic and detector and reducing the aperture are helpful,and reducing the two detectors＇ abaxial distance can improve their measurement uniformity.The test result using 10 ns-width 1.064 μm laser shows that,the probe can measure the pulsed laser energy from 50 nJ to 8 mJ within the error of ±9%,and output the laser waveform at the amplitude between 0.7 V and 1.4 V.According to the deduced illuminance transfer coefficient formula,the diffuse transmittance of the translucent ceramic was tested to be 0.60 with an error of ±1.7%.