Does anyone have beam expander night pics

[willpine]

Hi
I was looking for beam expander pics at night, and maybe comparison b/w the laser without.
i did a quick search but didnt see it on here.
thanks

 

[RA_pierce]

I do.
If you can wait until I get out of class today I can upload them here.

It's a 10X beam expander + >650mW 532nm laser. I no longer own this laser, but it was incredible!

Here is a video for now:

 

[willpine]

Hey i think i have seen that video before. The beam didnt really look bigger. I thought the expander would make the beam diameter bigger? That's why i wanted to see a night shot and maybe would look more what i imagined. Did you sell yours here a couple months ago? I saw someone did, and i meant to ask then. Ya a night shot would be great thanks for the post and look forward to the other one

thanks
w

 

[Sinuhesieda]

Hey i think i have seen that video before. The beam didnt really look bigger. I thought the expander would make the beam diameter bigger? That's why i wanted to see a night shot and maybe would look more what i imagined. Did you sell yours here a couple months ago? I saw someone did, and i meant to ask then. Ya a night shot would be great thanks for the post and look forward to the other one

thanks
w

They works both way; to expand and accumulate by changing the focus.

 

[Benm]

You can always try for yourself with binculars. When set for focus at infinity, they work fine as a makeshift beam expander. I have a set of 10x50 bresser binculars that expand the beam diameter tenfold (obvously), and also reduce the divergence by about that amount.

 

[Cyparagon]

Hey i think i have seen that video before. The beam didnt really look bigger.

It is bigger at the aperture. It was changed slightly to allow focusing at a longer distance. The dot would not be that small if no expander were used. It can also be used to simply expand the beam, but that doesn't work well for long distance burning.

 

[Benm]

For burning you can set it up like that indeed, but beam expanders are mostly used to reduce divergence... getting the output lines as paralel as possible. At distances of over about 100 meters, the resulting dot is smaller with the expander than it is without.

 

[mod101]

I always though beam expanders worked by enlarging the beam so the beam was still wider than initially but over a long distance like in the picture it would retain its size better than an unexpanded beam

 

[qumefox]

I always though beam expanders worked by enlarging the beam so the beam was still wider than initially but over a long distance like in the picture it would retain its size better than an unexpanded beam

Beam diameter and lowest possible divergence are tied fairly closely to each other, So you are correct. But what Cyparagon was saying is that this particular beam expander has been modified to have adjustable focus, so the beam can be focused to a point at longer ranges.

 

[mod101]

Oh ok that makes more sense.

 

[Cyparagon]

Yes. Your drawing is correct, too.