利用石英晶体微天平测量激光参数的实验研究

摘要

A QCM(quartz crystal microbalance) system for measuring the parameters of high power laser is built up and tested under the irradiation of short-time(25 ms to 2 s)and long-time(>20 s) laser.The experimental results on the quartz crystal indicate that the reso-nance frequency will first rise linearly,and then to a steady value under the irradiation.Dur-ing the rising period,the frequency increment is proportional to the laser energy.When it reaches the steady state on long-time irradiation,the incremental frequency compared to that front-end irradiation is proportional to the laser power.The laser energy that the QCM can endure is less than 7 mJ and the laser power that the QCM can measure is less than 80 mW. The power density that the QCM can endure is up to 2 .3 kW·cm-2 ,while the irradiation time can be up to 60 s.Therefore,it is concluded that the variation of the resonance frequen-cy of the QCM irradiated by the laser is due to the change of the inner temperature field and stress field.%为了测量高能激光参数,基于石英晶体微天平测量高能激光功率或者能量的思路,搭建了石英晶体微天平测量系统,分别针对短时间(25 ms 到2 s)激光辐照和长时间(20 s以上)激光辐照以及石英晶体谐振器耐辐照能力开展了实验研究,并对实验结果进行了初步分析。实验结果表明,石英晶体谐振器受激光辐照时,谐振频率首先线性增加,然后趋于稳定。频率增加过程中,频率变化量与入射激光能量成正比；长时间辐照后频率趋于稳定,谐振频率相对于辐照前的变化量与入射激光功率成正比。测量系统最小可分辨的能量在7 mJ 以下,最小可分辨的功率在80 mW以下,耐受激光功率密度不小于2.3 kW·cm-2,辐照时间不小于60 s。分析认为,石英晶体谐振器受激光辐照后,谐振频率发生变化与辐照后晶体内部温度场和应力场的变化有关。