do you want 0 mrad???use binoculars...!work for me.

[realista]

helklo boys..... i tryed to use a binoculars with my 30mw green laser.. and i musyt say it makes a 1,3 cm beam diameter.. but very collimated.... at infinity!!

furst i focus the binoculasr at long distance,,, than i put the laser in ONE lense... and my other eye in the others........ wow.. i see a VERY LITTLE DOT that goes to infinity.. and rest supersmall at incredible distance... trust me... if not real 0mrad.... 0.1 for sure.

i am starting to think.....and what if a buy a monoculars at LOW PRICE at dealextreme? (they sell it) could work well?

surely for the mrad yes.... but... how about the lense?can block too light? i notice that it loose some power with binoculars... so i think that REAL beamexpander...ises special glass for 532nm.... but bey... if someone has power to sell with an over 100mw green laser... it is not a big problem to loose some power..... and everyone can do a beamExpander at low price

 

[rangedunits]

Thanks for the advice, i think you meant Under 0.2mRad.


Here mine:

Il eventually need to have an adapter for my/the EVO Pro.

 

[Grix]

Doesn't work on neither a binocular or a DX monocular for me.

 

[diachi]

0 mRad is not possible. The beam will always diverge/converge somewhat. But by using a beam expander ( telescope/binocular etc ) you can achieve really low divergences.

 

[Deleted member 8382]

How is this used? and how does that work? I'm curious

 

[diachi]

How is this used? and how does that work? I'm curious

There are a few different setups you can use, but they all do basically the same thing. They expand the beam first with a concave lens and then collimate it again with a convex lens, giving a larger beam diameter but lower divergence. A 10x beam expander increases beam diameter by a factor of 10 but reduces divergence by a factor of 10.

 

[Krutz]

good hint to use one lens of the binocular for the laser and the other for watching.. its so obvious, i didnt think of that.. ;-)

manuel

 

[Deleted member 8382]

uhm... and how is this that the divergence is proportional to the diameter of the beam?

 

[realista]

good hint to use one lens of the binocular for the laser and the other for watching.. its so obvious, i didnt think of that.. ;-)

manuel

thanks however. yes.... is a good idea use one lense for watch... and the other 1 for the divergence
but no one comment explained me IF there chould be some problem using 532nm with a normnal binocular..... if it loose too power or not. i think there are specific lense for green light... to leave pass 99% of light with NO DISPERSION of colour. i notice less bright the laser with binoculars.... mmh.. about 30% less

 

[realista]

Thanks for the advice, i think you meant Under 0.2mRad.


Here mine:

Il eventually need to have an adapter for my/the EVO Pro.

HEI.. is it the dragonlasers beamExpander? it is the best price i found for a certified GREEN beam expander. other beam expander i think do loose power ....

 

[Deleted member 8382]

HEI.. is it the dragonlasers beamExpander? it is the best price i found for a certified GREEN beam expander. other beam expander i think do loose power ....

and they are out of stock... xD

 

[millirad]

It depends on the quality or even existence of an AR coating on the binocular lens. A sharp drop in beam strength exists when the coating is absent. Wavelength specific coatings would provide the least amount of power loss.

 

[dr-ebert]

A common binocular contains many optical elements for correcting color dispersion (chromatic aberration) and for turning the image right-side-up - you don't need either in a beam expander; all air/glass interfaces reflect and scatter a certain amount of light so the fewer there are, the better. A simple astronomical (!) finderscope with just two lenses would be best from a light loss standpoint (they're generally anti-reflection coated as well).

 

[Krutz]

interesting! its pretty obvious, but i didnt think of that by myself. good idea about the finder.. will have a look for a small one, perhaps extract the (two) lenses and build me a more appropriate housing..
uhm, since we`re at it already: a 10x magnifying finderscope or binocular would enlarge the beam by 10x as well.. not? as long as the beam isnt magnified so much that it is partially blocked from the now too-little lens-diameter..

manuel

 

[rangedunits]

Anyone know how to make an adapter for my Evo pro?

 

[Glutton]

Funny, I actually have 2 dx monoculars on order for this very purpose.

I plan on removing the lenses and fitting them with some AR coated lenses from edmunds optics.
check a thread called http://laserpointerforums.com/f49/dioptika-beam-expander-42814.html all about this topic. You can search the posts and find a lot of usefull information on beam expanders and how they work. Thanks to HIMNL9 and steve001 I have a good understanding of beam expanders now.