利用脉冲宽度为50 fs,中心波长为800 nm,重复频率为1000 Hz的飞秒激光脉冲在LiNbO3晶体上烧蚀表面衍射光栅,采用632.8 nm的He-Ne激光测量不同光栅的衍射效率.在激光脉冲能量和光栅常数相同的情况下,烧蚀速率由20μm/s增大到200μm/s时,所加工光栅的1级衍射效率从1.7%增大到2.3%;如果光栅常数和烧蚀速率不变,将激光脉冲能量由70 nJ增大到110 nJ,所加工光栅的1级衍射效率从1.9%减小到1.3%;随着光栅常数的增大,在LiNbO3晶体上烧蚀光栅的各级衍射效率也随之增加.对实验结果进行理论分析表明,可以通过提高烧蚀速率、降低激光脉冲能量和增大光栅常数来提高飞秒激光加工光栅的衍射效率. The diffraction efficiency of the gratings on LiNbO3 crystal was ablated by a femtosecond laser pulse with a pulse width of 50 fs, a center wavelength of 800 nm and a repetition frequency of 1000 Hz, and the diffraction efficiencies of different gratings were measured with a 632.8 nm He-Ne laser. When the ablation rate increases from 20μm / s to 200μm / s with the same pulse energy and grating constant, the first order diffraction efficiency of the processed grating increases from 1.7% to 2.3%. If the grating constant and ablation rate are not The energy of laser pulse is increased from 70 nJ to 110 nJ, and the first-order diffraction efficiency of the processed grating is reduced from 1.9% to 1.3%. With the increase of the grating constant, the gratings on the LiNbO3 crystal are ablated at all levels The diffraction efficiency also increases.The theoretical analysis of the experimental results show that the diffraction efficiency of the femtosecond laser processing grating can be improved by increasing the ablation rate, reducing the laser pulse energy and increasing the grating constant.