高斯光束和超高斯光束在空气介质中的成丝特性研究

研究了入射激光光束空间形态对飞秒激光光丝的影响。系统地比较了高斯光束和超高斯光束在空气介质中形成的光丝的特性。理论研究结果表明,在相同的条件下,相比于标准高斯光束,超高斯光束在轴上位置处更有利于获得高的钳制光强以及等离子密度。该研究结果表明,通过改变入射光束空间形态可以实现对光丝特性的调控。在实验上,该方法可以简单地通过在光路中插入圆形光阑,或者利用空间光调制器将传统的高斯光束转变为超高斯光束。

Comparative investigation of properties of filament generated by Gaussian and super-Gaussian beam

We investigate the influence of the incident laser beam shape on femtosecond filamentation in air.The properties of filament generated by Gaussian and super-Gaussian laser pulses are compared systematically.It is found that the super-Gaussian beam can produce on-axis higher intensity and plasma density in filament in comparison with the standard Gaussian laser beam under the same conditions.And the possible reasons are discussed qualitatively.Our finding enables manipulation the properties of filament by changing the shape of the incident beam.In experiment,this method can be applied by simply inserting the circular aperture to the light path or using the spatial light modulator to change from standard Gaussian profile to super-Gaussian profile.