为了获得大频差双频激光输出,设计了一种由偏振分光棱镜和半波片组成的新型双折射滤光片作为激光纵模选择元件。将这种新型双折射滤光片置于激光二极管(LD)抽运Nd∶YAG激光器的谐振腔内,实现了单纵模激光振荡。绕激光腔轴旋转半波片以改变波片快轴与偏振分光棱镜偏振面之间的夹角,发现单纵模激光输出功率发生周期性变化,变化周期约为π/2。设计并实验研究了一种LD抽运双腔大频差双频Nd∶YAG激光器,其两个驻波谐振腔(即直线腔和直角腔)共用相同的激光介质和纵模选择元件,1064 nm激光p分量和s分量分别在直线腔和直角腔内同时以单纵模振荡,改变每一谐振腔的长度可以调谐腔内单纵模激光的谐振频率,从而实现双频激光频差调谐。实验观察到1064 nm正交线偏振双频激光的频差在27~113.4 GHz范围内可调谐。 In order to obtain a large frequency difference dual-frequency laser output, a novel birefringent filter consisting of a polarizing beam splitter and a half-wave plate is designed as a laser longitudinal mode selection element. This novel birefringent filter is placed in the cavity of a laser diode (LD) pumped Nd:YAG laser to achieve single-longitudinal mode laser oscillation. The half-wave plate is rotated around the laser cavity axis to change the angle between the fast axis of the wave plate and the polarization plane of the polarization splitting prism. It is found that the laser output power of the single longitudinal mode changes periodically with a variation period of about π / 2. An LD pumping dual-cavity high frequency difference dual-frequency Nd:YAG laser was designed and experimentally studied. The two standing wave resonators (ie, the linear cavity and the right-angle cavity) share the same laser medium and longitudinal mode selection element. The 1064 nm The p and s components of the laser oscillate in a single longitudinal mode at the same time in the linear cavity and the right-angle cavity, respectively. Changing the length of each cavity can tune the resonant frequency of single-mode laser in the cavity to achieve dual-frequency laser frequency tuning. The experiment shows that the frequency deviation of 1064 nm orthogonal linearly polarized dual-frequency laser can be tuned in the range of 27 ~ 113.4 GHz.