偏振激光诱导金属表面周期条纹结构机理的研究

Study on Periodic Ripples on Metallic Surfaces Induced by Polarized Lasers

不同偏振态激光诱导金属表面产生条纹结构的研究有很多,但对形成该结构的机理分析较少。通过在光路中插入1/4波片用于改变飞秒激光偏振态,使产生的偏振激光垂直照射到金属钨表面产生条纹结构,进而研究这种条纹结构的产生机理和激光偏振态对产生这种结构的影响。研究发现,不同偏振态的飞秒激光与对应诱导产生的条纹结构之间具有很好的一致性。当1/4波片周期性单向旋转时,激光偏振态随之周期性变化,金属表面形成的条纹结构的方向也相应地随之改变,最大偏转角度约π/4。对这种条纹方向随波片旋转而变化现象的机理进行了理论分析,分析表明不同偏振态的飞秒激光诱导金属表面产生条纹结构的方向由激光进入双折射晶体(如1/4波片)后分解的电矢量分量决定。

There are many studies on phenomenon of periodic ripples induced by polarized lasers on the surface of metal, but studies on mechanism are few. Femtosecond laser is polarized through inserting a quarter waveplate into the beam path, and then vertically transmitted onto the surface of tungsten to produce ripples.And then the mechanism of the inducing ripples and influence of polarization of laser on the inducing ripples is studied. It is found that periodic ripples have a good correspondence with polarization of femtosecond laser.When the quarter waveplate rotates periodically of single direction, the polarization of femtosecond laser and the direction of periodic ripples change accordingly. The maximum inclining angle of ripples is about π/4. An analysis of the mechanism of matter that direction of ripples changes along with rotating of quarter waveplate is given. Theoretical analyses indicate that the direction of periodic ripples induced by polarized laser is primary decided by electricity vector components grown at the moment of laser flies across birefringent crystals, for example a quarter waveplate.