IR

[ngiapy]

hey guys i need some help here. i told my friend about the damaging effects of ir in >50mw dealextreme lasers due to their inadequate ir filter and this is his reply, which really stumped me. would need some help to explain how ir damages our eyes

Heat is IR and you are exposed all the time. Never heard of IR damaging the eye. There are equipment purposely generate IR for treatment (comsumer product), I own one from Philip rated at 300W. If IR is so dangerous, it will never be sold so easily.

The link here to Wikipedia on IR, you may want to read about it, Infra Red and it didn't mention anything about damaging the eye.

I guess the IR filter is to filter off the heat and to prevent interference to the green light. So, for a GLP to work, a IR filter is a MUST, see article from Wiki on GLP Green Laser Pointer

I will be concerned if it generates UV, especially short wavelenght UV which causes cancer.

 

[xanatos]

Well, start by showing him these videos of 60Watts of IR:

http://www.laserpointerforums.com/forums/YaBB.pl?num=1196556614/0#0

Next, tell him there is a difference between "heat" IR and COHERENT IR, which delivers a GREAT amount of radiation to a small area.

There is a LOT on this forum about how easily IR can blind someone who doesn't respect what it can be in laser form.

Lastly, if he isn't a really good friend, tell him his eyes are his own and if he wants to risk his eyesight for life - it's his problem, you warned him.

If he IS a really good friend, he'll at least give your admonisions some warranted attention and read the info on this forum about how easily IR can blind. IR is probably the most dangerous of the laser radiations.

Be sure he sees what "just" 60 watts can do to the turkey (which is meat). That 60 watts is concentrated COHERENTG energy, not 300 watts spread out all over with asynchronous wavefronts.

Personally, I wouldn't be so kind. Anyone who approaches something they really do not know anything about, but believes they know it all already - is bound to have the environment itself teach them the lessons they need. Unfortunately, these lessons are often harsh, and permanently memorable.

It's his choice.

Dave


PS - Bonus round - ask him why I can burn a HOLE in a CD case with my 200 milliwatt red laser, but I can't even light a match by focusing the image of a 300 watt lightbulb on it. After all, if his logic applied, the 300 watt bulb should be able to develop greater focused energy than a puny 200 milliwatt (that's 0.2 watts) red diode, right?

 

[pseudonomen137]

There is a mistaken rumor out there that IR is very dangerous compared to green. I think this is what you've getting confused over.

IR laser light is not dangerous because its IR, its dangerous because its high power laser light. 100mW of green can cause more damage to the eye than 100mW of IR but 100mW of IR can damage the eye just the same.

The other danger though is that near-IR isn't very visible so you can be hit with a lot of dangerous near-IR without knowing it.

A 60W lightbulb will emit ~1-3Watts of actual optical output. That, if all focused onto your eye, could easily destroy it. Its diffuse and emitting in all directions though - thats where a laser differs. Even a portable laser can pack the better part of a watt into a miniscule <1mm^2 space.

The IR filter on a greenie doesn't really affect the green output. However on lasers without IR filters the power ratings get exaggerated by the IR, and you end up paying big bucks for 532nm power that isn't there. That's why unfiltered lasers suck!

 

[xanatos]

True - and I'd add to the mix that the fact you can't SEE IR makes it that much more dangerous. You can be getting a whopping wad of coherent IR into your eye and not even know it- and just wonder why the lights are getting dimmer and dimmer!

Dave

 

[pseudonomen137]

and just wonder why the lights are getting dimmer and dimmer!

Actually, you end up seeing blood across your eye - something that often causes shock in its victims. Speaking of which, I sell IR protection goggles

 

[xanatos]

Actually, you end up seeing blood across your eye

Oh yeah! That oughta get his attention!

D

 

[ngiapy]

wow guys that really help! thanks loads!

 

[wooooooolazer]

Yeah i personly think its not bad if the laser outputs what they say in just green and you get a "bonus" of ir, since it will help it burn altho it does spread out more than it . My true 5 can pop a baloon in a few seconds cause alll the ir, i had seen in lots of places that they have an ir filter but i guess i got one without because it does emit quite a bit of ir.

The only thing bad is you dont know when it reflects in your eye if its like 2 inch away from a mirror then the green wont reflect but the ir that spreads out will.

...lazer... ;D ;D ;D

 

[Cyparagon]

However the IR that diverges is inherently no longer concentrated, is it?

tell him there is a difference between "heat" IR and COHERENT IR, which delivers a GREAT amount of radiation to a small area.

There's a difference between Mid-IR (my laser) and Near-IR (other burner lasers), and also between conventional light, and coherent light.

 

[Switch]

No but it still sucks to look directly at a red diode (for example) with no lens, so that scattered IR, if it's a good 20 mW would still damage your eye up close, right? Especially if you're not knowing it and keep getting it in your eyes for a few months or years while you play with your laser.

Isn't there a place where we can buy IR filters to put on our dx lasers? ;D

 

[pseudonomen137]

No but it still sucks to look directly at a red diode (for example) with no lens, so that scattered IR, if it's a good 20 mW would still damage your eye up close, right? Especially if you're not knowing it and keep getting it in your eyes for a few months or years while you play with your laser.

Isn't there a place where we can buy IR filters to put on our dx lasers? ;D

Its not really the same situation with the greenie. You may be getting a few 10s of mWs of IR out of the high end NewWish lasers, but although it is more divergent, the majority of the power still syncs with the green beam. Only time I can see it causing real trouble is if you have laser goggles on for green, take a direct hit to the eye, and the IR still passes through. The IR that spreads out past the green will be so diffuse and you'd still have to nearly be taking the green in the eye that its hardly worth discussing.

IMO, the main problem with the IR is that it hypes of the power ratings. DX/NewWish 200mW units aren't 200mW, plain and simple. If you really are worried about the stray IR though, you can buy a filter through Nova, and I even have a few quality Coherent filters I could sell.