通过数值求解亥姆霍兹(Helmoltz)波动方程，研究了激光辐照薄膜靶产生的不同厚度、不同标尺长度的薄层等离子体对激光的反射、透射及吸收(逆轫致吸收，共振吸收)率随入射角的变化情况。小角度入射时，短脉冲(～ps量级)激光打靶产生的标尺长度较小的等离子体对激光的吸收率比长脉冲打靶时低。但在大角度入射时，短脉冲打靶时等离子体的吸收率反而比长脉冲打靶时高。

By solving Helmholtz wave equations numerically, the absorption, reflection and transmission of a plasma layer with different scale-lengths and thicknesses varying with incident angles and polarizations are studied. For smaller incident angles,the absorption by a short scale length plasma produced by a short laser pulse (～ps) is lower than that of a long laser pulse. But for bigger incident angles, the absorption of a short laser pulse is higher than that of the long pulse.