摘要
当激光束的横向光斑尺寸是波长量级甚至是亚波长量级时,傍轴近似失效,必须采用非傍轴描述.高斯光束作为球面激光腔的横基模,迄今为止已提出很多方法来描述非傍轴条件下的高斯光束.赫兹矢量呈高斯分布的另类非傍轴TM高斯光束,是麦克斯韦方程组的高斯波解,是共焦腔和半共焦腔的本征值.为了进一步分析其传输特性和指导应用,在近场将另类非傍轴TM高斯光束的积分解表示成f的幂级数形式的级数解,并退化到傍轴条件给出了傍轴解.所给出的级数传输解对传输距离和初始高斯半宽度有一定的适用范围.在远场利用静止位相法给出了解析的光场,同时对另类非傍轴TM高斯光束的源分布和传输强度分布作了计算和分析,显示了其与一般非傍轴高斯光束的差异.
When the transversal spot size of the beam is of the order of the light wavelength and even the light subwavelength, the paraxial approximation fails and the nonparaxial description must be adopted. As the Gaussian beams are the fundamental modes of laser cavities with spherical mirrors, many different approaches, by far, have been presented to describe the Gaussian beams beyond the paraxial regime. Another kind of nonparaxial TM Gaussian beams, whose Hertz vector is Gaussian distribution, are the rigorous solutions of Maxwell＇s equations for a confocal resonator. In order to further analyze the propagation characteristics and supervise the application, the series expressions of another kind of nonparaxial TM Gaussian beams are obtained and expressed as series of f in the near field. Moreover, the paraxial solutions are also given as reducing the paraxial condition. The applicable range of series solutions presented here depend on the propagating distance and the initial Gaussian half width. At the far field, the analytical optical field is presented by means of the method of stationary phase. The distributions of the light intensity at different propagating distances are calculated and analyzed. The results reveal the discrepancy between another kind of nonparaxial TM Gaussian beam and general nonparaxial Gaussian beam.
出处
《兰州大学学报（自然科学版）》
CAS
CSCD
北大核心
2007年第5期130-135,共6页
Journal of Lanzhou University(Natural Sciences)
基金
浙江林学院科研基金(2351000508).
关键词
非傍轴光束
TM高斯光束
光束传输
级数解
nonparaxial beam
TM Gaussian beam
beam propagation
series solution
