What damage can an IR laser cause?

Several years ago I decided to buy a blue laser and did some shopping around. I finly decided on one and made the order. I'm still not sure if they miss advertised the laser or if they sent me the wrong one, but what showed up was a 400mw 808-980nm IR laser pointer. At the time I was not as familiar with wavelengths and honestly didn't even know that infrared lasers existed. As soon as I figured out what it was I baught the appropriate glasses to protect my eyes. To be honest, the thing scares the crap out of me. I never use it but I do have a few questions about it. Like I said, before I knew what it was I used it without glasses and could see a dim red-ish dot. I thought it was broken but now knowing that the laser should be invisible, why could I even see a dot when I used it? But my main question is, what kind of damage can IR lasers cause? I know they're regaurded as more dangerous than lasers in the visible spectrum but what exactly happens if you were to shine it in someone's eyes? Is it instant blindness? Does vision blur or get worse over a few days? Will you just have a black dot in your vision?

And a side note, why do these even exist? I looked at it through some night vision goggles and that was neat, but that even gets old after just a minute.

It depends on the wavelength really - at the wavelength you have the damage would be pretty much the same as any visible laser of the same power. At longer wavelengths, such as the 10.6um from a CO2 laser, the light will be absorbed by the cornea and as such the damage will occur there.

IR Lasers are considered more dangerous simply because you can't see where the beam or any reflections might be going, reducing your ability to react to a potential accident.

The dim red glow is not from the IR laser light, it's a secondary visible emission you get with IR diode lasers.

They exist for many different purposes, 808nm diodes for example are used in the large majority of DPSS lasers as a pump for some other solid state laser. They have uses in IR illumination as you've already seen, etching/cutting, communications, and many many more applications.

The are actually pretty dangerous. The light is nearly invisible, but with near-IR lasers like 808 or 1064 nm the light gets focussed on your retina quite well and causes as much damage as visible light would at equal power - but you are not aware of it, will not blink and allow it to continue for a longer period of time.

Diffuse reflections aren't that dangerous unless you put your eye right on them, but reflections off shiny materials (say some crumpled tinfoil) can be quite a hazard.

As for the dot being somewhat visible: With 808 nm it's quite likely that you are able to see that light under the right conditions and with that intensity. 400 mW of 650 nm red light is a blindingly bright dot, the sane amout of 808 nm is hardly visible in daylight (though it is in darker conditions).

Be VERY careful with these lasers and always ware protective eyewear, and accident can easily happen and chances are you will not be even aware of it until it's too late.

Benm said:

The are actually pretty dangerous. The light is nearly invisible, but with near-IR lasers like 808 or 1064 nm the light gets focussed on your retina quite well and causes as much damage as visible light would at equal power - but you are not aware of it, will not blink and allow it to continue for a longer period of time.

Diffuse reflections aren't that dangerous unless you put your eye right on them, but reflections off shiny materials (say some crumpled tinfoil) can be quite a hazard.

As for the dot being somewhat visible: With 808 nm it's quite likely that you are able to see that light under the right conditions and with that intensity. 400 mW of 650 nm red light is a blindingly bright dot, the sane amout of 808 nm is hardly visible in daylight (though it is in darker conditions).

Be VERY careful with these lasers and always ware protective eyewear, and accident can easily happen and chances are you will not be even aware of it until it's too late.

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See, that's really my question. Would you be immediately aware of damage caused from an infrared laser? You both mentioned they work in the same way a visible laser would by focusing on the retina so I would assume so, but with a visible laser, I would expect that if you got hit in the eye, everything would be washed out and as your vision recovered, you'd be left with a black spot that wouldn't heal. I guess what I'm asking is if you were to get hit in the eye with an infrared laser, would you just see a black spot appear as it destroyed your retina immediately or would your eyesight gradually get worse over the next few days?

..."would you just see a black spot appear as it destroyed your retina immediately or would your eyesight gradually get worse over the next few days?"

Yes to both.

WizardG said:

..."would you just see a black spot appear as it destroyed your retina immediately or would your eyesight gradually get worse over the next few days?"

Yes to both.

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Yikes. Fair enough. After using the laser without glasses I had always been afraid that I may have gotten hit with a reflection or damaged my eyes by looking directly at the dot but not notice it until some time later.

Jasonlis said:

Yikes. Fair enough. After using the laser without glasses I had always been afraid that I may have gotten hit with a reflection or damaged my eyes by looking directly at the dot but not notice it until some time later.

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A direct hit would probably be perceived as a bright flash even if it was IR due to retinal cells randomly firing as they were killed by the heat. This would be followed by perception of a dark spot in the visual field and, due to bleeding and inflammation, gradual (seconds to hours) deterioration of vision.

Your OP said you had bought what was supposed to be a blue laser. DPSS blue lasers exist and are generally pretty expensive. How much did you pay? I'm just wondering if what you have is actually a blue pointer with misaligned crystals so the only light making it out of the business end is 808nm IR from the pump diode.

WizardG said:

A direct hit would probably be perceived as a bright flash even if it was IR due to retinal cells randomly firing as they were killed by the heat. This would be followed by perception of a dark spot in the visual field and, due to bleeding and inflammation, gradual (seconds to hours) deterioration of vision.

Your OP said you had bought what was supposed to be a blue laser. DPSS blue lasers exist and are generally pretty expensive. How much did you pay? I'm just wondering if what you have is actually a blue pointer with misaligned crystals so the only light making it out of the business end is 808nm IR from the pump diode.

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It's been a few years so it's hard to remember but if I remember correctly, it was somewhere around the $80 range. At first glance it looks like a generic laser pointer but is built much sturdier than a generic pointer. It has a small blue light that lights up when you press the power button, it runs off of two normal AAA batteries, and won't work unless you use a key. The key can be put in 3 positions: off, on, and another that I can't figure out what it does. I've looked at it through night vision and there is nothing being emitted when it's in that 3rd position.

For $80 a few years ago chances are it isn't a blue DPSS laser and was never going to be.

Sounds like it was incorrectly advertised.