电光晶体调谐的外腔反馈半导体激光器

Electro-Optical Crystal Tuned External Cavity Diode Laser

报道一种用电光晶体实现快速调谐和调制激光频率的方法。在Littrow型外腔反馈半导体激光中插入LiNbO3晶体,利用LiNbO3晶体的电光效应,通过改变晶体电压来调节激光器的有效腔长,可以对激光频率进行快速的调谐和调制。采用该方法,自制外腔反馈半导体激光器的调谐频率可达到2kHz,它的调谐范围为350MHz,激光频率调谐系数约为1.06MHz/V,用饱和吸收光谱观测频率调谐的效果。快速激光频率调制可以应用在稳频技术上,将外腔反馈半导体激光器调制在5～100kHz频率下,均获得了87Rb原子D2线的饱和吸收光谱的色散信号,并实现了激光频率在饱和吸收峰上的长期稳定。

A method of fast laser frequency tuning and frequency modulation by electro-optical crystal is reported. Due to the electro-optical effect of LiNbO3 crystal, fast laser frequency tuning and modulation of the Littrow type external cavity diode laser （ECDL） with an electro-optical crystal is demonstrated by changing the effective laser cavity length with the voltage on the crystal. By this method, in the homemade ECDL, the tuning range of 350 MHz is achieved with tuning rate of 2 kHz, the tuning coefficient is about 1.06 MHz/V, and the effect of laser tuning was observed by saturated absorption spectrum. The fast frequency modulation can be used on the frequency stabilization. The dispersion signal of the saturated absorption spectrum of D2 line of ^87 Rb atoms is achieved with the laser frequency modulation rate of 5--100 kHz, and the laser frequency is long-term stabilized on the peak and cross peak of saturated absorption spectrum of the D2 line of ^87 Rb atoms.