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



Beam stopper?

MajorLazor

Member
Joined
Jun 5, 2019
Messages
46
Points
8
Wondering what you use to safely stop a beam? I'm getting a 2W PL-E mini from jetlasers, and am assuming it's not good to just have it pointed at a wall or something.
 



diachi

Well-known member
Joined
Feb 22, 2008
Messages
9,748
Points
113
Beefy black anodized heatsinks work well too. The fins act as a bit of a baffle, helping contain any specular reflections.
 

MajorLazor

Member
Joined
Jun 5, 2019
Messages
46
Points
8
Beefy black anodized heatsinks work well too. The fins act as a bit of a baffle, helping contain any specular reflections.
Something like this, maybe?

Or actually, this one might be better:
 
Last edited:

MajorLazor

Member
Joined
Jun 5, 2019
Messages
46
Points
8
Or how about this?
 

reloader45

Active member
Joined
Mar 17, 2019
Messages
172
Points
28
Hello,

what do you want?. Do you like to see the focused beam on a target or do you want to absorb all the light on the target? In this case I would suggest to use a black box with black velvet inside and a hole at the target side.


best regards

Edgar
 

MajorLazor

Member
Joined
Jun 5, 2019
Messages
46
Points
8
Hello,

what do you want?. Do you like to see the focused beam on a target or do you want to absorb all the light on the target? In this case I would suggest to use a black box with black velvet inside and a hole at the target side.


best regards

Edgar
If I have it set up on my desk for burning, I just want to have the beam terminate on something besides the wall. At what distance will a 2W 445 laser no longer burn things?
 

steve001

Well-known member
Joined
Jun 3, 2007
Messages
2,367
Points
113
If I have it set up on my desk for burning, I just want to have the beam terminate on something besides the wall. At what distance will a 2W 445 laser no longer burn things?
Lol farther than the distance to any wall in your house.
Another solution would be to use a short negative focal length lens that will diverge the beam
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
16,316
Points
113
I have many 2+ watt lasers that I can focus on any of my walls with no harm to the wall or any marks to show that this was done. I suppose it depends on the paint used, but a white wall won't absorb like a black item will so it is less likely that your wall would be damaged. White is more reflective than dark colors, especially black. Now, I would not try this with a 7 watt laser at a short distance because the power density of the beam is high at very short distances. The further out you get the safer this becomes as long as you haven't used optics that keep the divergence of the beam low. I have used lasers up to 4 watts against my white walls without harm of any kind.
 

RedCowboy

Well-known member
Joined
Jul 10, 2015
Messages
8,256
Points
113
Lol farther than the distance to any wall in your house.
Another solution would be to use a short negative focal length lens that will diverge the beam
I don't think it's a good idea to use any kind of glass beam stop not even a lens unless the whole system is bolted down, if it's not bolted down then it's a reflection hazard.
 

WizardG

Well-known member
LPF Site Supporter
Joined
May 9, 2011
Messages
737
Points
63
I don't think it's a good idea to use any kind of glass beam stop not even a lens unless the whole system is bolted down, if it's not bolted down then it's a reflection hazard.
Not 100% sure but I think what Steve had in mind was to focus the laser to as fine a point as possible for burning at a range of a few inches. Focused that way the beam would then diverge rapidly away from the 'work' area.
 

MajorLazor

Member
Joined
Jun 5, 2019
Messages
46
Points
8
Not 100% sure but I think what Steve had in mind was to focus the laser to as fine a point as possible for burning at a range of a few inches. Focused that way the beam would then diverge rapidly away from the 'work' area.
That is what my green laser does now. The spot on the wall is probably 4-5" across when I have it focused close, but that laser is under 100 mW.
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
16,316
Points
113
In order to burn anything with a <100 mW laser you need to focus the beam on your target about 2 to 3 inches away. That will give you a beam profile of less than 1 mm. You need that kind of power density to get a 75 mW laser to melt or burn anything. Of course the beam will diverge quickly past this focal point, so you needn't worry about a beam stop as the size of the dot at a couple of feet is quite large.
 




Top