a noobs confusion

[addicted]

I've read over the "read this first FAQ's" page thoroughly and all the links and videos from that page, along with some other tutorials, youtube videos, and other read-ups found.

This is the confusing stuff(to me) that I can't find anywhere-


quote from felesmagus.com/pages/lasers-cheap.html first part of "Safety Matters" section.
"if you're relying on laser goggles rated at 532nm to protect your eyes, you may as well wear no goggles at all because they won't do anything to block the IR, and worse than nothing, you might take some extra risks in the belief that your eyes are protected since the green dot is dull and doesn't hurt to look at! Additionally, the IR is not as well-collimated, so it spreads out more, which means you might not even know you're getting dangerous specular reflections of IR in your eyes, because the green is not reflecting your way." And I did read the whole page, I think it clicks with some of the other things he said but I guess I don't get the connection.

He's saying that 532nm goggles won't protect your eyes and won't block any IR. I thought goggles designed for 532nm(green) protect your eyes from all harm(although not long periods of direct exposure) and same with all the other goggles made for and used with a specific color. This question is going to loop with all my other questions(and trying to figure out what he means) going through my head until my brain explodes[smiley=shocked.gif] so why don't I just wait for some help on that one first.[smiley=smiley.gif] Thanks.

 

[Chicxulub]

Protective goggles have a coating on them that will block specific wavelengths within a few nm. The goggles designed for a certain wavelength will not protect you 100%, but they are good for accidental, split second exposure, the goal is to make the amount of light getting into your eyes be low enough that your natural blink reflex can handle it.

Some goggles can be coated for more than one wavelength, there's actually members here selling them, but I couldn't tell you who they are. I've seen them in signatures.

 

[Ace82]

In my opinion, people stress over ir WAY too much. To not use the correct safety goggles while using lasers because of ir leakage, is absurd. There is allot of fuss about ir that has people running scared. Just get a good laser with an ir filter, then when you are burning stuff using your safety goggles the ir threat will be allot less. The little amount of ir that leaks through is also uncollimated, so it spreads almost like a flash light. Here's some more safety facts if you haven't read already.

http://en.wikipedia.org/wiki/Laser_safety

 

[Chad]

In my opinion, people stress over ir WAY too much.

Yes, they do. However, just because it might not be as dangerous as they think, doesn't mean that there isn't any danger. Not using safety glasses just because of IR is a pretty dumbass thing to say, and needs to be ignored... IR, however, doesn't. I've had my eyes damaged by IR before, and trust me, it isn't fun. Needless to say, I make sure all of my DPSS lasers have IR filters. Stop saying that there isn't much of any danger at all, because THERE IS. You can still damage your eyes with an uncollimated laser... so why say that just because the IR is poorly collimated, that it won't do anything? Check your facts.

 

[moond0ggie]

The more expensive models of green lasers should have an IR filter.

You would never look into the business end of a laser, so the safety
goggles are mostly helpful in protecting your eyes from errant reflections
of 532 light or the intensity of light from viewing the beam on a white wall or
through fog, smoke, etc.

You are also viewing IR wavelengths, & though they are not focused,
you should still exercise caution.

The most risky application is burning objects because you are viewing a fixed
focused dot for an extended period.


Viewing the beam while directed towards the sky is probably the safest
application.


You can get an idea of where the IR light is emitting by viewing the side of the 532 beam through a cell phone camera or any cheap camera.

 

[addicted]

Thanks for the help everyone. From what I understand, you're all saying that what he is trying to say is that using goggles for any color won't do a thing, although he's really just overdoing the fact that they don't block 100% of IR, which the little that they don't won't actually harm your eyes. Although don't mess with IR, use goggles. Hopefully I understood that correctly.

Next question(s) about cheap 5mw lasers...
I take it that a cheap 5mw laser won't have an IR filter but since it's under 5mw it's ok to view without goggles(rite?), but not above that.

I know there's a mod to make 5mw lasers into burning lasers, I guess you bypass the IR filter buy burning some part of the driver(I thought an IR filter was a lens and can't be done with the driver?), is this harmful even with goggles because there's so much IR? And, since this mod seems to work, couldn't you push a ton of mw out of any 5mw diode?

Don't IR filters lower the mw by a ton, and make the light more dim? And an IR filter is no substitution for goggles, it only helps protect you from IR that much more?

Thanks.

 

[Switch]

You're getting it all wrong.Goggles that block green, don't necesarily block IR (the cheap ones don't anyway, or I would be all over them...)So, if your laser isn't IR filtered, while you're protected from green , you're not protected from IR.

If you're laser is IR filtered, AND you're wearing goggles, you're as safe as you can be.

Yes, the IR filter is a piece of glass and not on the driver.Modding low powered lasers to a higher power refers feeding more current into the diode thus overdriving it.And no you can't squeeze out a ton of mW out of a 5mW diode, it can only handle a limited amount of current before it blows and becomes useless.

IR filters don't "lower mW by a ton", they typicaly lower the green output by 2-5% but lower the IR output by something like 98%.That's they're whole point, to get rid of most of the IR.

 

[Chad]

Modding low powered lasers to a higher power refers feeding more current into the diode thus overdriving it.And no you can't squeeze out a ton of mW out of a 5mW diode, it can only handle a limited amount of current before it blows and becomes useless.

Well, yeah, you will blow the diode with too much current, the real reason is that the crystals become oversaturated... depending on the size and efficiency, they can only put out so much green (or blue, or yellow, or whatever).

 

[addicted]

Chad, I read in your basic FAQ's page that red diodes don't produce IR. I was looking at the two laser diodes sold on stontek, and the 808nm is a red beam. The link to the IR filter on your FAQ page is for 808 and 1064nm lasers, so I'm assuming a red 808nm beam does produce IR, and the 650nm red is what doesn't.

I take it that the 808nm and 1064nm IR filter won't work on green lasers.

A couple of questions about the sony 16x diode, is it 650nm(no IR) or 808nm? what mw is it capable of? And is it better than the 808nm 200mw diode? Thanks!

 

[Kenom]

This is a list of all the colors and the associated wavelengths as well as visibility to the human eye.  You will see that 808nm is very dark red.  In all actualitiy your eye cannot see it very well at all.  So what you see is 1/100th of what is actually there.  If you could see what was truly there, it would blow you away.  I have a 1 Watt (1000mw) 808 pointer and to the unprotected eye, it looks like a 5mw 660nm pointer.

 

[rangedunits]

Thanks Kenom for the pics, did you took pictures of the button?

 

[VillageIdiot]

I have a 1 Watt (1000mw) 808 pointer and to the unprotected eye, it looks like a 5mw 660nm pointer.

Damn, don't want to be looking at the dot of that thing for long

 

[GooeyGus]

Infrared light is NOT A SAFETY ISSUE when it comes to excess spray from a green hand-held. IR IS A SAFETY ISSUE when viewed on its own.

I've said it many times, but it doesn't hurt to say it a few more times... since it hasn't seemed to catch on yet.

The issue with wanting an IR filter comes from that fact that IR can skew power readings. Thus, an IR filter is important if you want to figure out the true amount of green that you are getting from your laser. Somewhere along the lines, the desire for an IR filter for power readings got skewed into a desire of an IR filter for safety. The simple fact is that the amount of IR that actually makes it out the end of a green laser is a fraction of what the actual green light is. Depending on the lens and pump setup of the laser, it can just spray out or it can be a part of the green beam (although diverging a bit faster) but ultimately the laser is putting out so much more green light than is it IR light that you need to worry about the green, not the IR. Even with a pen that is spewing IR like crazy, you might get 20mW of HIGHLY divergent infrared light. Could this be harmful if it was shined straight into your eye? Of course! But the 100mW of tightly focused green is going to cause a lot more damage than the 20mW of IR ever will.

Now, lasers that are completely IR are very dangerous. Not that IR light is any more damaging than visible light, but that fact that you cant see where potential reflections are going make it hazardous. Double that with the fact that you can shine the laser straight into your eye (don't) and not even know its blinding you just makes it downright dangerous.

In the end, with a green laser, worry about the green. That's what's going to cause the damage.

 

[GooeyGus]

Chad, I read in your basic FAQ's page that red diodes don't produce IR. I was looking at the two laser diodes sold on stontek, and the 808nm is a red beam. The link to the IR filter on your FAQ page is for 808 and 1064nm lasers, so I'm assuming a red 808nm beam does produce IR, and the 650nm red is what doesn't.

I take it that the 808nm and 1064nm IR filter won't work on green lasers.

A couple of questions about the sony 16x diode, is it 650nm(no IR) or 808nm? what mw is it capable of? And is it better than the 808nm 200mw diode? Thanks!

808nm IS infrared light, so an 808nm diode only produces infrared light, which can be considered 'red'. 808nm is the same wavelength that pumps crystals in green pen lasers. A 650nm diode wont produce infrared light, because they are 650nm and nothing else (IR is considered to be ~750nm and up). The sony diode is 650nm, and I'm not sure exactly what power it's capable of. Somewhere over 200mW though I'm sure. The 808nm/1064nm IR filter will work perfectly on green lasers. The diode in a green laser, as mentioned above, is 808nm. This diode pumps an nd:yvo4 crystal, which then produces 1064nm light to pump the KTP, which doubles the wavelength to 532nm (green). Therefore, with a green laser one can expect to get a small amount of 808/1064nm light along with the green. The filter will block most of that excess light, and will let the 532 pass, leaving you with only green.

Hope that helped clear some things up