针对飞秒激光作用光学该实验条件下薄膜过程中损伤阈值与激光波长的关系问题，利用近红外波段波长可调谐的高重频飞秒脉冲激光，对可见光滤光片光谱通带的过渡区域进行了背向损伤实验，测量了不同波长下的平均功率密度损伤阈值，并从飞秒激光作用的雪崩电离过程出发，推导并计算了该阈值与薄膜干涉场分布的关系，理论结果较好的预测了不同波长下平均功率密度损伤阈值的发展趋势.研究表明，该实验条件下薄膜的飞秒激光损伤是整体行为，同一样品中，干涉场分布的平均值越高即膜层中瞬时驻留的激光能量越大时，相应损伤阈值越低.

The mechanism of damage to the optical coatings of filters induced by femtosecond laser at different wavelengths was studied. A near infrared wavelength tunable femtosecond laser was used to rediate the visible wavelength filter from backside. The wavelengths were selected in the transitional region of the filter pass band and the corresponding threholds of average power density were obtained. Based on the avalanche ionization process, the relationship between damage threshold and distribution of interference field was investigated. The theoretical results can predict the trend of thresholds. The results indicate that the damage behavior of a coating irradiated by femtosecond laser pulses exhibits an overall behavior. The damage threshold decreases with the increase of transient residual energy in the multi-layer structure of the coating.