微小孔非傍轴衍射光束传输特性的研究

基于非傍轴标量光束横截面上光强的精确定义,对桶中功率和二阶矩定义的光束束宽、远场发散角和M2因子等进行了比较研究.以平面波的微小圆孔衍射光束为例,进行了详细的数值计算.结果表明,桶中功率定义的光束束宽、远场发散角和M2因子较二阶矩定义的小,两种定义的M2因子都随束腰趋于零而趋向于零,桶中功率定义的光束束宽的传播规律与双曲线存在一定偏差.

Propagation Characteristics of Nonparaxial Scalar Beams Diffracted by a Small Aperture

Based on the accurate definition of light intensity of nonparaxial scalar beams at the transverse plane,a comparative study of the beam widths,far-field divergence angles and M2 factors defined by the power in the bucket and second-order moment is made.Taking the nonparaxial diffraction of a small circular aperture as an example,the detailed numerical calculation is performed.The results show that the beam width,far-field divergence angle and M2 factor defined by the power in the bucket are less than that defined by the second-order moment.Both M2 factors tend to zero as beam waist vanishes,the propagation of beam width defined by the power in the bucket is different from the hyperbolic law.