How to measure the divergence

[Wanjiru]

Hi everybody,

I want to measure the divergence on my look-alike deal-extreme green 30 mW laserpointer from laserbeam, a danish company.
Is the diameter only the brightest dot (on my laser the dot is 0,6 from 7 meters away) or is it also the slightly (and only slightly) darker outer ring? (here the dot is 1,2 cm from 7 meters away)
It makes a pretty big difference if the dot is 0,6 or 1,2 cm

Beforehand thanks

Wanjiru

 

[murrat]

How you measure it? I mean the brightest dot? With naked eyes?

 

[Wanjiru]

Kk, then my look-alike deal-extreme laser should have a 0,9 mm divergence? That can´t be right. Can it?

 

[RA_pierce]

Here are some links:
http://laserglow.com/index.php?lasertesting
http://www.pseudonomen.com/lasers/calculators/mRadCalculator.html