由于忽略激光能量分布的不均匀性,当前常用的非线性透过率方法得到的三光子吸收系数的拟合误差比较大.现有材料的三光子吸收截面还比较小,阻碍了人们对三光子吸收特性的应用.本文提出了一种精确的三光子吸收拟合方法,适合于各种能量分布不均匀的激光脉冲.合成了一种具有三光子吸收特性的对称型芴类衍生物2,7-二(4-甲氧基苯乙炔)-9-硫酮芴,三光子吸收截面较大,具有很好的激光脉冲光稳幅特性.
Three-photon absorption coefficient obtained by current nonlinear transmittance method has large fitting error because of uneven laser radiation distribution. Relatively small three-photon absorption cross section values of present nonlinear molecules restrict their practical applications. In this paper, an accurate three-photon absorption coefficient fitting method is presented, which is applicable for a variety of laser distributions. A fluorene-based derivative, 2, 7-bis(4-methoxyphenylacetylene)-9-thoine-fluorene, is synthesized. Apparent three-photon-absorption-induced optical stabilization effect is shown.