激光锁定F-P腔频率的有差锁定研究

External Optical Cavity Locked by Laser Frequency

基于有差伺服调节技术,实现了外置光学谐振腔的共振频率与钛宝石激光器工作频率的锁定。该技术采用压电陶瓷作为执行元件,通过对压电陶瓷的调制,实现了对透射激光功率的调制,并由锁相放大器解调获得伺服信号,该伺服信号经过高压放大器放大后控制压电陶瓷的伸缩来调控谐振腔的腔长,从而使腔的共振频率锁定在激光频率上。当激光工作于单一频率时,谐振腔的谐振频率可以长时间地与激光频率保持锁定,锁定后腔的透射光功率相对起伏的稳定性为2%。当激光频率扫描时,谐振腔的谐振频率可以在2GHz范围内不间断地与激光频率保持锁定。

With the peak-seeking servo-controlled technology based on a residual error,an external optical cavity can keep in resonance with the frequency of Ti-sapphire laser in the experiment. The servo loop uses a piezoelectric transducer （PZT） as a modulator,which modulates the intensity of the transmitted light passing through the cavity. The servo signal is obtained from the lock-in amplifier,then it is amplified by a high voltage amplifier,which adjusts the length of the cavity according to the laser frequency. In this approach,the resonant frequency of the cavity can be locked to the laser frequency for a long time as the laser operates in a fixed frequency and the relative fluctuation of output power from the cavity is lower than 2%. When the frequency of the laser scans,the cavity is also capable to follow the variation of laser frequency automatically in an uninterrupted range of 2 GHz.