摘要
从功率密度的二阶矩方法出发,对非傍轴余弦一高斯(CoG)光束的传输特性进行了系统的研究。结果表明,基于二阶矩定义的束宽在传输过程中满足简单的双曲线变化规律。非傍轴CoG光束的M^2因子不仅与偏心参数α有关,而且还与f参数有关。在1/f足够小时,M^2因子可小于1。当1/f→0时,远场发散角趋于渐近值63.435°。对于α=0(Ω_0=0)的特例,非傍轴CoG光束的M^2因子退化为非傍轴高斯光束的M^2因子。
Starting from the second- order moment of the power density, the propagation characteristics nonparaxial cosine- Gaussian （COG） beams have been systemieslly investigated. It is shown that the second - order - moment based beam width follows the simple hyperbolic law for propagation. The M2 factor of nonparaxial CoG beams depends not only on the decentered parameter a, but also on the f parameter. The M2 factor can be less than 1 when 1/f is small enough. As 1/f→0, the far - field divergence angle appronehes an asymptotic value of 00, max = 63.435°. For the special cases of α = 0 （Ω0 = 0）, the M2 factor of nonparaxial CoG beams reduce to the M2 of nonparaxial Gaussion beam.
出处
《激光杂志》
CAS
CSCD
北大核心
2007年第4期39-40,共2页
Laser Journal
