Tight beam on 405nm

[Ammar]

Thanks for the answer, dr-ebert.

Are there any "beam-thinners" available anywhere?
Why aren't they popular on this forum?

So if I would like to make a blu-ray beam thin as a DPSS-green beam,
what would the divergence be (approximately)?

Thanks.

 

[tony70516]

I am asking because I dont know.


This is possible.
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   Thick     I     LENS   I     --_    Focused Beam
   Beam    I    I __ --    
   I    I     __--
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But is this possible?


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Thanks!

yes of course its possible, buy a lens from nova, buy this lens
http://www.novalasers.com/NOVAstore/pc/viewPrd.asp?idcategory=6&idproduct=45
it focuses it into a line, not like convex or collimator which will focus to a focal point and than spread out again. also the 405-G-1 lens is always an option. its 35 bucks, but you have to figure out how to mount it in an aixiz, its not that hard if you know what your doing. or jayrob can sell you the completed module assembly with the lens for 55 bucks. its your call. good luck

 

[Arenared]

i think what he means is.. can it be shot out like a green laser .. thin straight beam all the way (infinity) no baseball bat.

 

[Deleted member 8382]

From what I know, you don't need 2 lens, if u put the diode exactly in the lens focal point you will get a beam.

lemme show you something

The effect is also everse, so if you put a light emisor at the focal point "F" you should get a straight beam. Ofc using normal light will make it disperse, but using coherent light... Voila! that's a laser

(Correct me if i'm wrong )

Yours,
Albert

 

[dr-ebert]

In principle that's right, that's exactly what the collimating lens does. Here, the shorter the focal length (FL) of the lens, the narrower the beam. However, I think the original question was how to "compress" an existing (collimated) beam.

Just try running your beam through a small telescope with low magnification, e.g. a 6x binocular or finderscope: into the objective lens (the big one), the beam exiting through the eyepiece should be thinner by the magnification factor (ignoring diffraction effects). Doing it the other way round will give you a beam expander.

 

[...]

You can try to compress the beam down all you want, but if you are looking at the beam/spot at night it is never going to look like a nice sharp beam like a green or 473nm blue would--it has a big halo around it. There is nothing you can do about that, it is an optical illusion because your eyes cannot focus of 405nm light, they just weren't designed for it.