Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

How to Register on LPF | LPF Donations

Wow, really tight beam, what's my divergence?

Joined
Dec 24, 2007
Messages
1,000
Points
63
My cheap little keychain red laser has one of the tightest beams I've ever seen in a pointer. At the source, it's dot is 3.5 by 2.5 mm. At fifty feet, it's 10mm by 7mm. That's always struck me as probably being first rate, especially considering it's just a keychain laser.

Does anyone know the math to figure out how many milliradians that is?
 





That would actually be less than 0.5 mRad.Probably around 0.4 if your measurments are accurate :P
 
Since you have such a large beam diameter (~3mm) the divergence isn't really that amazing TBH. You can always trade off diameter for divergence, so a thick beam with low divergence, or a thin beam with high divergence, or a medium beam with medium divergence are all basically equivalent.
 
ohh sorry, its about .5mrads, i looked over my math and was a tens place off when converting to mRads.

I'm glad to see my math was correct except for the 10's place. (i just sort of made it up remembering what i had learned from school)
 


Back
Top