基于锁相放大器和LabVIEW的激光功率测量系统

Laser power measurement systems based on lock-in amplifiers and LabVIEW

为了降低激光噪声对光学实验的影响,采用了锁相放大器配合光学斩波器进行降噪。斩波器将激光调制成某一特定的频率,并把该频率传送至锁相放大器作为参考信号,锁相放大器再利用相干检测的方式提取出有用信号。为了减轻实验过程中操作员的劳动,使用Lab VIEW平台开发了一套自动化软件系统,实现了实验操作和数据记录的自动化,极大地简化了操作流程。结果表明,与直接使用功率计测量激光强度的方法相比,该方法测量噪声从9.1%降低到4.7%;与人工记录数据相比,使用自动化软件系统节约了一半以上的实验时间。

In order to reduce the impact of noise on laser optical experiments,a lock-in amplifier and an optical chopper were used. The laser was modulated at a specific frequency by the chopper and the frequency was sent to the lockin amplifier as a reference signal. The useful signal was extracted with the lock-in amplifier based on the coherent detection method. In order to relieve the operator＇s labor during experiments,an automatic software system under LabVIEW software platform was developed to operate the experiments and record data automatically,which greatly simplified the operation process. The results show that measurement noise of this method reduced from 9. 1% to 4. 7% compared with laser intensity measurement with a power meter directly. The automatic software system saves more than 50% of time compared with manual recording of data.