激光冷却原子技术已在精密测量领域获得广泛应用,偏振梯度冷却技术是获得超冷原子的常用方法。偏振梯度冷却需要大范围减小冷却光频率,传统方案是用声光移频器的衍射光作为冷却光,通过改变声光移频器的移频量改变冷却光频率,但声光晶体移频带宽较窄,该方法冷却光频率移动不能充分进行,这严重限制了原子冷却的效果。介绍了一种可大范围改变冷却光频率的方法，该方法通过改变激光器输出频率来实现冷却光频率的改变,频率调谐范围可达120 MHz。该方法可获得更低温度和更多数目的原子源,满足高精度冷原子物质波干涉测量的需求。

Laser cooling atomic technology has been widely used in the field of precision measurement. Polarization gradient cooling is commonly used method to obtain ultra-cold atoms. This is achieved by using far detuned, low intensity optical molesses during polarization gradient cooling stage. In the conventional scheme, the diffracted light of the acousto-optic modulator is used as the cooling light, and the frequency of the cooling laser is detuned by changing the frequency of the first diffraction light of acousto-optic modulator. Due to bandwidth of the acousto-optic modulator narrow, the shift of the frequency can not be fully carried out, which severely limits the effect of atom cooling. A method is introduced to realize the frequency shift of the cooling light by the frequency hopping of the laser. This method increases the range of variation the laser frequency to 120 MHz, and facilitates the generation of lower temperature atomic sources.