Neo said: there is no vaccum.

送交者: steven 于 2012-05-17, 17:02:52:

回答: 史蒂文，你对激光熟悉么？由蓝隼于 2012-05-17, 16:51:58:

I am not an expert in this area, but I heard it is determine by the Rayleigh length which depends on the wavelength and beam waist.

I see. Is the beam waist the same thing as beam thickness? - 蓝隼 (88 bytes) 2012-05-17, 17:06:41 (665642)
- not really, beam thickness, beam diameter - steven (570 bytes) 2012-05-17, 18:19:17 (665659)
oops, determined by... (无内容) - steven (0 bytes) 2012-05-17, 17:06:22 (665641)