What is the highest wavelength that is visible?

:yh:

Personally I can't see a bit of 808nm, but its possible there may be some IR flouresence off the surface your pointing at.

Solonar;

I've seen that (somewhat unique) very dim, but very DEEP rubylike color coming from *some* IR LEDs (not laser diodes)... for such an LED (NOT a laser!!!, a low output IR LED) you have to place your eye very close to the LED in a dark room. It's almost at the limit of perception. So it probably isn't fluoresence.

Considering the frequency band (at the edge or close to it of the visible spectrum), some people would see it more than others, and some people wouldn't see it at all.

As I indicated earlier... I had always ASSUMED that this was just a deep red by-product of the diode, I was ASSUMING that I wasn't actually seeing any "IR".

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Okay... so IF some of us are vipers, then should we stay away from Japan? I hear they get nervous around bipedal reptiles.

I can actually see 808nm pretty vividly... not amazingly, but it's pretty bright. At 200mW, I can see it pretty damn well. Never tried focusing it before on a far away object, but I will once I build my IR pointer.

On a side note, I wish that IR and UV were a different color to our eyes, instead of just deep red and deep violet.

This is making me very curious, then. I've never been close to an 808nm laser. If I ever get the chance, or I can find a cheap mid-output one, I'd like to try it.

AFTER I get my DIY parts list together. (for another wavelength).

On a diffused black surface I can see 808nm quite easily..
It is not bright for the power compared to a 650nm wavelength...


Jerry

I think the consensus would actually be that most people can see 808 nm light as long as its bright enough. Personally i don't have any problem seeing the IR from a 808 pump either, even if its just a small one for a 5 mW greenie.

The problem is, that its all bloody dangerous - normal red light can easily appear 1000 times brighter at the same power density, and you would blink or look away from that! So do not use your eyes to observe 808 unless you are really really sure what you are doing.. though if you were, you wouldn't ;D

Most people can see the IR from 850nm LEDs.

http://laserpointerforums.com/f44/how-deep-can-you-see-53856.html#post759689 Reports of 980nm laser light being visible

There is a DEFINITE variance from person to person, this occurs on the low end of the wavelength spectrum as well. I have a very hard time seeing a 808nm (I can see it, but its EXTREMELY DIM), however, a friend of mine can see an 808nm laser alot easier. He can point out the dot almost instantly.

In the same aspect, I have a 375nm blacklight pen which is visible to me, easily, but my friend has a much harder time seeing that than i do.

I suppose it varies from person to person, but I would say ~850nm is the highest that is visible.

Is it the friend who sees 808nm easily the same one who can't see 375nm as well as you?
Always interested in accounts of the (high or low) limits of visibility.