摘要
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(PIB)和二阶矩定义的非傍轴标量高斯光束的束宽、远场发散角和M2因子等进行了详细的数值计算,并与傍轴标量高斯光束的传输特性进行了比较。结果表明,桶中功率定义的远场发散角和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。束腰参量w0较小时三种定义的光束束宽、远场发散角和M2因子存在较大差别,随着w0的增大三种定义的光束参量趋于一致。指出了非傍轴标量高斯光束功率密度二阶矩及传统光强二阶矩理论的有效性与束腰参量w0的关系,这对非傍轴光束传输特性的研究具有参考价值。
Based on the accurate definition of light intensity of nonparaxial scalar beam at the transverse plane,a detailed numerical calculation of the beam widths,far-field divergence angles,and M^2 factors defined by the power in the bucket（PIB）and second-order moment are performed for nonparaxial scalar Gaussian beams,and the result is compared with that of paraxial scalar Gaussian beams.The results show that the far-field divergence angle and M^2 factor defined by the PIB are less than those defined by second-order moment.Both M^2 factors tend to zero as beam waists vanish.The beam widths,far-field divergence angles,and M^2 factors defined by the three definitions have great differences when the parameter of beam waist w0 is relatively small,and the beam parameters tend to unity with the increasing of w0.The relationship between the beam waist parameter w0 and the validity of the second-order moment theory of paraxial and nonparaxial scalar Gaussian beams are pointed out.This will provide reference for the study of the propagation characteristics of nonparaxial beams.
出处
《激光与光电子学进展》
CSCD
北大核心
2010年第9期111-115,共5页
Laser & Optoelectronics Progress
基金
国家自然科学基金(50776084)
火灾科学国家重点实验室开放课题(HZ2009-KF08)资助课题
关键词
物理光学
传输特性
二阶矩
桶中功率
非傍轴高斯光束
physical optics
propagation characteristics
second-order moment
power in the bucket
nonparaxial Gaussian beam
