激光二极管抽运频差可调谐双频固体激光器的研究

研究了激光二极管抽运的可调频差的双频固体激光器，激光增益介质为2mm厚的1at%掺杂Nd:YAG薄片.对谐振腔产生稳定双频激光的条件作了分析，用琼斯矩阵计算了谐振腔内各处电场矢量的偏振态，证明了双频激光两个电场矢量偏振态之间总是正交的.两个偏振激光频率间隔由改变λ/4波片快轴之间的夹角实现调谐.实验中使用腔内标准具实现单频运转，然后插入双λ/4波片使单纵模激光频率分裂，实现了激光器的双频输出.实验中得到双频激光稳定运转时频差的上限约为1.3GHz；由于强模竞争现象的存在，实验中所观察到的频差下限为50MHz. 100MHz拍频时得到的双频激光输出功率为85mW. 关键词： 激光技术 固体激光器 双频激光

The study on diode-pumped two-frequency solid-state laser with tunable frequency difference

The laser diode pumped two-frequency solid-state laser with tunable frequencydifference is investigated, the medium is a 1at% doped 2-mm thick Nd:YAG chip. The condition of stable two-frequency oscillation operation is analyzed, the polarization is calculated by Jones matrix in different locations at the resonator. It is proved that the two-frequency electric field vectors are orthogonally polarized everywhere, the frequency difference tuning can be realized by changing the angle between the fast axes of two quarter-wave plates. In the experiment, single-frequency oscillation was obtained with the help of an etalon, then longitudinal mode frequency splitting resulted in the two-frequency oscillating operation by inserting two quarter-wave plates. The obtained maximum frequency difference was 1.3GHz, the minimal was 50MHz because of the strong mode competition. Due to the loss anisotropy of the etalon, the output power is not very stable when tuning the frequency difference, 85mW two-frequency output power was obtained with 100MHz beat note.