介绍一种M_e^2<1而M^2>1的激光束

A Laser Beam with M^e_2<1 but M^2>1

文献[1～2]报导了等效光束质量因子M^2_e＜1的激光束，并称之为"超衍射极限"的光束．本文模拟计算出一种M^2_e＜1而M^2＞1的激光束，从而说明M^2_e＜1与M^2＜1并不"等效"．M^2_e＜1的激光束其M^2是否也＜1是一个尚待澄清的问题。

In literatures[1 - 2]it was presented that a kind of laser beams with M<1 wasgenerated,which were regarded as super - diffraction limit light beams. In this paper a laser beamwith M<1 but M>1 has been simulated. It demonstrates that M<1 is not equivalent to M<1 ,Is the M2-value 0f their laser beam (with M<1)less than 1 too?'is a problem to be solved.