M 2 factor of four-petal Gaussian beam
周国泉, 樊 艳
M 2 factor of four-petal Gaussian beam
Zhou Guo-Quan(周国泉) and Fan Yan(樊艳)
中国物理B . 2008, (10): 3708 -3712 .  DOI: 10.1088/1674-1056/17/10/029