Laser side-spill

[LEDbeam]

Not even sure if that's what it's called, but I think you get the idea. When I use my laser and am near a wall, I notice a splattering of light that emits directly to the side (and slightly in front) of the host. There is also such light on the opposite side but nowhere else. I just wanted to ask about whether or not this scattered light is generally safe to the unprotected eyes. Sometimes I like to hold the laser at arm's length and off to one side to view the beam from the side, but that means being hit directly with the scattered light that is emitted to the sides. Since that light is very scattered and not part of the concentrated beam, is it generally safe?
The laser I have is 700mw, 520nm.

 

[StardustSprinkles]

Technically anything over 5mW isn't eye-safe even for a moment, and seeing as your laser is 700mW the splatter you're seeing is likely above 5mW.

The splatter could be a few things, one being a dirty lens that could be cleaned with compressed air or a q-tip/cotton swab. Occasionally these diodes are made with a different beam shape i.e. rectangle rather than standard circular dot, so when it leaves the aperture of the laser it catches the edge and light scatters.

Either way to be safe probably don't look into it.

 

[paul1598419]

What you have is an artifact. It is usually the lens. The collimated light is what you need to keep away from your eyes.

 

[LEDbeam]

What you have is an artifact. It is usually the lens. The collimated light is what you need to keep away from your eyes.

Yep, I figured it was an artifact of some kind. I took a closer look at things and found something interesting. Inside the focusing ring, there are 2 slots on the inside. One is directly across from the other. So I stood next to a wall and turned on the laser to see if the light was somehow coming from those (even though the slots aren't open to the outside), I found that the light splatter that being emitted to the sides is actually opposite to the slots. So I had to turn the laser 90 degrees to see the light splatter on the wall. Weird!

 

[paul1598419]

I doubt the screw slots are causing this. That would truly be unusual.

 

[Encap]

You should return it for repair or replacement due to poor beam quality and artifacts.
Email the seller some photos and complain maybe they will offer to take care of it if returned or offer a partial refund. Worth a try.

 

[LEDbeam]

If the dot is anything like the photos you posted in the ND filter thread you should return it for repair or replacement due to very poor beam quality and artifacts.
Email the seller some photos and complain maybe they will offer to take care of it if returned or offer a partial refund. Worth a try.

Is this the thread? https://laserpointerforums.com/threads/using-nd-filter-to-dim-a-60-70mw-488nm-492nm-laser.111174/

I didn't post anything there. But my beam is really good. It's a green laser, so it has a sharper focus than most. No problem there.

 

[GSS]

Like Paul mentioned, those 2 opposite slots you see inside the focus knob are slots on the lens to help screw the lens in.
They aren't part of the focus knob, the focus knob is there to help not burn your fingers while focusing.
If you already know this i'm sorry.

What diode and lens type do you have and where did you buy the laser?
Some green lasers diodes are called G ball diodes. They have a set unfocusable lens on the diode can thats in the projector that way.
Builders will pop off the can with the fixed lens so they can use another lens to focus the laser.
Alot of times this will cause artifacts and it will never be perfect but there are ways to tame it with a different style lens.

Can you post pics of the spot and tell us what laser is about?

 

[RedCowboy]

I often use a shroud to soak up wide cast aberrations.
A length of black card stock works well and in hand held builds you can use a small extension ( m9x0.5 ) to lock down an infinity focus and use a little length of card stock inside it, then an emptied out m9x0.5 lens barrel and thumb wheel as a retainer or your own bit's and pieces, the longer and tighter the length of card stock ( absorber ) the better your results.

 

[GSS]

I was going to bring you up and mention your rounded black card stock method!
No LIe!

 

[LEDbeam]

Like Paul mentioned, those 2 opposite slots you see inside the focus knob are slots on the lens to help screw the lens in.
They aren't part of the focus knob, the focus knob is there to help not burn your fingers while focusing.
If you already know this i'm sorry.

What diode and lens type do you have and where did you buy the laser?
Some green lasers diodes are called G ball diodes. They have a set unfocusable lens on the diode can thats in the projector that way.
Builders will pop off the can with the fixed lens so they can use another lens to focus the laser.
Alot of times this will cause artifacts and it will never be perfect but there are ways to tame it with a different style lens.

Can you post pics of the spot and tell us what laser is about?

I wouldn't be able to tell you the lens type or much of anything else since I bought it assembled. I don't know the technical details of how it's made since I'm not knowledgeable about those things. What I can tell you is that it's a Jlasers 700mw 520nm.
The spot is very bright and my camera doesn't take good pics of it since the brightness is pretty overwhelming.

 

[LEDbeam]

I often use a shroud to soak up wide cast aberrations.
A length of black card stock works well and in hand held builds you can use a small extension ( m9x0.5 ) to lock down an infinity focus and use a little length of card stock inside it, then an emptied out m9x0.5 lens barrel and thumb wheel as a retainer or your own bit's and pieces, the longer and tighter the length of card stock ( absorber ) the better your results.

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That's a really good idea to block and sidespill!

 

[paul1598419]

Personally, I've had pretty good luck finding lenses to mange this.

 

[GSS]

I wouldn't be able to tell you the lens type or much of anything else since I bought it assembled. I don't know the technical details of how it's made since I'm not knowledgeable about those things. What I can tell you is that it's a Jlasers 700mw 520nm.
The spot is very bright and my camera doesn't take good pics of it since the brightness is pretty overwhelming.

Knowing its from Jlasers is a good start.

When I joined this forum I also knew nothing. My little chrome focus knob fell off and I thought I broke my laser. I panicked and private messaged 3 members. I also didn't know what a diode looked like and was shocked when I saw how small they were, especially the 3.8 size 405's WL diode and the 5.6 size 445 WL M140 diode.
I realize what I just said might mean nothing now. Just keep lurking and reading posts, old ones too which might be better.
There weren't alot of different laser colors 5 years ago. Mostly 405nm, 445nm and 520nm.

It also a shame that alot of good members left and there isn't alot help threads now with pics of builds but if you look for oldie posts you will learn more.
Go to seller DTR's site and you can see what parts are needed that he sells to get a idea..

 

[GSS]

Just want to ad on what Paul mentioned.
JLaasers seems to only sell and use 2 element lenses. Not sure what members think of them.
Try a 3 element lens maby as its the cheapest but tames the spot better??

 

[Encap]

You shouldn't have to go through the DIY learning problems of finding and experimenting with parts that may work, modifying with a different lens, and/or doing a makeshift adaptations with cardboard extension tubes and so on to make your recently new laser work the way it should from the get/go without any side-spill.

Return it for repair, replacement or refund if they they are all like that and buy a better quality laser from a different maker or vendor.