Infrared "seeing" glasses

[SenKat]

Agreed, Pseudo - everyone on here that has seen my "dangeropus demo" video has seen 808nm IR as well. There is a HUGE gaping hole in the research being done here - I can plainly see 808nm emission, as a matter of fact I have seen 980nm emissions as well - I actually have a few diodes here that are 980nm wavelength - do not have neough Aixiz modules to pop one in and show it off, since I have no desire to waste those diodes yet but trust me - on the one I tested it was definitely visible with no issues.

The 808nm pen that Pseudo let me review is CLEARLY visible - as a matter of fact, the glasses I have that block IR DO block it, so you only see the point of ignition, but without them on (yes, I HAD to peek once) it is a cherry red VERY dim glow....when shining on something - I did not look down the barrel, otherwise I would not be typing this message !

G !

 

[pseudonomen137]

Haha, I hate to argue with the person backing me up, but are you 100% sure those are 980nm diodes? The last time I saw the spec for 980nm visibility on Sams I caculated what powers it would take to be reasonably visible, and it was some huge magnitude of watts that would probably have destroyed any surface you could have seen it on.

Or perhaps your eyes have some hightened response in that region? I have a box of 978nm 260mW diodes and they were completely invisible to me. I even threw one out once because I was being stupid: I applied power, saw no output, so I assumed I had killed the diode. Only after I trashed it did I remember it was supposed to be invisible, and that's when I laserchecked the next one at 300mW

 

[steve001]

[quote author=steve001 link=1186500381/0#13 date=1187927760]Ok' I did a lot of poking around and the limited for human vision appears to be 750nm. There is one reference out to 780, but anything beyond that is invisible because the eye does not contain receptors sensitive to longer wave lengths

Steve, I think you have a lot more poking to do. I know for a fact Sam's laser faq has references to very low visibility specs into the 900-1000nm range.

Better than any random citation though, you CAN see 808nm... I can see 808nm. Don't believe me? Buy one of my IR pen lasers. I've even seen the BEAM of an 808nm before, although we are talking several Watts and lots of fog.

If you're buying a lightbulb, sure, it entirely impractical to consider any output past 750nm. When we're talking about shoving hundreds of mW into areas just a few mm in diameter though, even 808nm is unmistakably visible.

Actually, check out this vid: http://youtube.com/watch?v=31LfI4k9MA8
The 400mW 808nm spot is pretty true-to-life to my vision (its very dim, but there's no doubt its there)[/quote]


I will continue to look for a definitive answer. I've looked at sams laser faq and I believe the info to be in error. Don't you find it odd that all of the sites put the limit at 750 possibly 780nm and none of them even hint that visibility extends to such wave lengths you and Senkat mention ?

 

[SenKat]

Steve001 - take a peek at the video I made ! Seriously, man - do it !

G !

 

[pseudonomen137]

I will continue to look for a definitive answer. I've looked at sams laser faq and I believe the info to be in error. Don't you find it odd that all of the sites put the limit at 750 possibly 780nm and none of them even hint that visibility extends to such wave lengths you and Senkat mention ?

To be honest? No. I find it odd that I showed you a vid of how visible an 808nm laser is, and yet you continue to try to convince me light is invisible past 780nm.

Again, the sites that list 750nm and 780nm are likely going on the fact that the visibility past those wavelengths is "negligible" for any conventional lighting - the main reason why we care about photopic efficiency. The story changes when it comes to the concentrated energy of lasers.

I will again invite you to buy one of my 808nm lasers - I have yet to hear a single owner of an 808nm not be able to see the dot. You can also just take apart a CD writer and check out the 780nm diode which you'll also find is visible. If I weren't so lazy, I'd go and find/convert/upload the vid I made of a 808nm visible beam, but that other vid I linked should hold you over. That way if you can't find the info in theory - you can prove it in practice.

And yeah, I know Sam's FAQ can't be infallible, but as someone who's seen 808nm spots from lasers 50mW to 20W, I'm inclined to question the accuracy of the sites that say 780nm is invisible much more than I'm inclined to question the Sam's figures.

 

[steve001]

Steve001 - take a peek at the video I made ! Seriously, man - do it !

G !

Where can I find it ?

 

[steve001]

Best information so far
http://4colorvision.com/files/photopiceffic.htm

Similar to Sams info
http://www.everything2.com/index.pl?node_id=805569

 

[pseudonomen137]

Okay, I just checked with the 1988 CIE function here: http://members.misty.com/don/photopic.html

It only goes up to 780nm, but it indicates that 400mW of 780nm would be roughly 10 less visible than 1mW of 660nm. 1mW of 660nm is actually quite visible, and I see no reason to doubt that, by extension, 808nm would be invisible. I'm not saying 980nm is clearly visible to the average person, but I'm not gunna listen to anyone who tells me I can't see past 780nm.

 

[SenKat]

http://stonetek.org/VIDS/808nm_demo.wmv is the link to the video....also, check in the companies and reviews section where I reviewed Pseudo's IR laser....I have a thread there with a vid or two, I believe !

G !

Anywho - this just really goes to show you that you cannot believe everything you see written up on the web, especially when you have a few experienced folks telling you taht you are incorrect in your assesment ! There is irrefutable proof out there that your assumptions regarding higher wavelengths are false, so no amount of pics and vids will prove to you any different. I unfortunately look upon this discussion as folks arguing that the sky is indeed blue to our eyes, or the sun is yellow, or that the earth is round, when back in columbus' time it was thought to be so - honestly, it does not matter really what you think, or believe - the facts speak for themselves, and you are 100% incorrect, and that is pretty much that. sorry if this sounds a little harsh, but seriously - look at the evidence, and also listen to those that have been into lasers for a while, and have seen this with our own eyes. with my vision as horrible as it is without glasses on, I can still see that wavelength with ZERO issues - so enjoy the videos !

G !

 

[steve001]

Okay, I just checked with the 1988 CIE function here: http://members.misty.com/don/photopic.html

It only goes up to 780nm, but it indicates that 400mW of 780nm would be roughly 10 less visible than 1mW of 660nm. 1mW of 660nm is actually quite visible, and I see no reason to doubt that, by extension, 808nm would be invisible. I'm not saying 980nm is clearly visible to the average person, but I'm not gunna listen to anyone who tells me I can't see past 780nm.

By that logic there would be no end to the frequencies you can see.
It's not am matter of physics alone, but one entirely of biology. here's something you could try. Aim the beam through a diffraction grating to see what other frequencies are being produced. look at this site http://ilewg.lpi.usra.edu/education/fieldtrips/2005/activities/ir_spectrum/ ]
maybe humans can see light at these longer wavelengths

 

[pseudonomen137]

[quote author=pseudonomen137 link=1186500381/15#23 date=1187965464]Okay, I just checked with the 1988 CIE function here: http://members.misty.com/don/photopic.html

It only goes up to 780nm, but it indicates that 400mW of 780nm would be roughly 10 less visible than 1mW of 660nm. 1mW of 660nm is actually quite visible, and I see no reason to doubt that, by extension, 808nm would be invisible. I'm not saying 980nm is clearly visible to the average person, but I'm not gunna listen to anyone who tells me I can't see past 780nm.

By that logic there would be no end to the frequencies you can see.
It's not am matter of physics alone, but one entirely of biology. here's something you could try. Aim the beam through a diffraction grating to see what other frequencies are being produced. look at this site http://ilewg.lpi.usra.edu/education/fieldtrips/2005/activities/ir_spectrum/ ]
maybe humans can see light at these longer wavelengths[/quote]

Yes, I actually kinda meant that. Looking at it mathematically, which is not my ideal way to look at it but I have a point to make: If you assume the perception of EM is completely continuous, and not quantized (which it probably is, so this isn't entirely valid); as you move further away from 555nm, the relative intensity of perception would asymptotically approach 0, but never actually reach it (except as wavelength approaches the infinite or infinitesimal). The value may, and does get to a point where its entirely impractical to see that wavelength, and for me I'm pretty sure that value is between 900 and 1100nm, but you can't really say "yes, at exactly 782.9896nm you stop seeing EM" or something like that.

Or at least that is my understanding of it. I realize it is not purely physics and I am trying to approach the issue with my limited knowledge in physics, mathematics, biology, and psychology. That is on the theory end though. In practice, you CAN see 808nm light (without aid of fluorescence or other tricks) and to me, that is more telling than any amount of theory. If a brilliant scientist came to the conclusion that you can't see light past 700nm, and I then showed him the spot of an 800nm laser... well, you see where I'm going.

I can shine my lasers through a diffraction grating, but I'm talking about 808nm (+/- a few nm of course) AlGaAs diodes, so its not like we're gunna see other major lines start popping up. What am I supposed to be looking for through the grating?

PS: Sorry this thread has kinda turned into a silly argument.

 

[Aseras]

I've seen 980 and even 1064 if it is "bright" enough.

It's just very very dim. they all look the same, a vague unfocusable red color. Same with the UV end, you get the strange violet color that unfocusable with your eyes.

there's not a direct cut off, just a level where it slowly fades more and more, and you need more to see it. It's the same with your hearing. if you get into a very quiet room you can hear things that go far outside the normal hearing range.

with the highend IR, it is drowned out by the visible light, so beyond 850nm or so it's nearly invisible unless you darken the room and have LOTS of power. you are not going to ever get to see a 10,6knm co2 laser, but I guarantee you I can make you see a 1064 yag in a the right environment. You have to use a beam dump since at the power levels you need things tend to fluoresce or combust.

 

[Aseras]

[quote author=steve001]
By that logic there would be no end to the frequencies you can see.
It's not am matter of physics alone, but one entirely of biology. here's something you could try. Aim the beam through a diffraction grating to see what other frequencies are being produced. look at this site http://ilewg.lpi.usra.edu/education/fieldtrips/2005/activities/ir_spectrum/ ]
maybe humans can see light at these longer wavelengths[/quote]


Plenty of animals and insects particularly see well into the far IR range. Others see much less visible light and more UV.
What humans see, the "spectrum" as we know it, is particular to our species. every other species in the world doesn't see the same colors and shades and things we do. Even humanity as a whole doesn't see exactly the same. There' plenty of variation out there from the "norm". There's not a predefined limit for anything. that's where statisticis comes in to play. you could say that 85% of people cannot see above 900nm in normal conditions. But there will always be a freak that can see to say 1200nm. There's also plenty of people who cannot see anything, but they did see an atomic bomb flash go off back in the 40's & 50's. With the right conditions, and enough power you can extend the limits of just about everything, it just takes a LOT more effort.

 

[steve001]

[quote author=steve001 link=1186500381/15#25 date=1187967576][quote author=pseudonomen137 link=1186500381/15#23 date=1187965464]Okay, I just checked with the 1988 CIE function here: http://members.misty.com/don/photopic.html

It only goes up to 780nm, but it indicates that 400mW of 780nm would be roughly 10 less visible than 1mW of 660nm. 1mW of 660nm is actually quite visible, and I see no reason to doubt that, by extension, 808nm would be invisible. I'm not saying 980nm is clearly visible to the average person, but I'm not gunna listen to anyone who tells me I can't see past 780nm.

By that logic there would be no end to the frequencies you can see.
It's not am matter of physics alone, but one entirely of biology. here's something you could try. Aim the beam through a diffraction grating to see what other frequencies are being produced. look at this site http://ilewg.lpi.usra.edu/education/fieldtrips/2005/activities/ir_spectrum/ ]
maybe humans can see light at these longer wavelengths[/quote]

Yes, I actually kinda meant that. Looking at it mathematically, which is not my ideal way to look at it but I have a point to make: If you assume the perception of EM is completely continuous, and not quantized (which it probably is, so this isn't entirely valid); as you move further away from 555nm, the relative intensity of perception would asymptotically approach 0, but never actually reach it (except as wavelength approaches the infinite or infinitesimal). The value may, and does get to a point where its entirely impractical to see that wavelength, and for me I'm pretty sure that value is between 900 and 1100nm, but you can't really say "yes, at exactly 782.9896nm you stop seeing EM" or something like that.

Or at least that is my understanding of it. I realize it is not purely physics and I am trying to approach the issue with my limited knowledge in physics, mathematics, biology, and psychology. That is on the theory end though. In practice, you CAN see 808nm light (without aid of fluorescence or other tricks) and to me, that is more telling than any amount of theory. If a brilliant scientist came to the conclusion that you can't see light past 700nm, and I then showed him the spot of an 800nm laser... well, you see where I'm going.

I can shine my lasers through a diffraction grating, but I'm talking about 808nm (+/- a few nm of course) AlGaAs diodes, so its not like we're gunna see other major lines start popping up. What am I supposed to be looking for through the grating?

PS: Sorry this thread has kinda turned into a silly argument.[/quote]

What am I supposed to be looking for through the grating?

Light produced by led emissions. While looking at Sams site I came across this Visibility of Near-IR (NIR) Laser Diodes and Spectra of Visible and IR Laser Diodes http://www.repairfaq.org/sam/laserdio.htm#diovon2

 

[pseudonomen137]

Well, if you're implying that the visibility I'm seeing is because of other emissions, the link you just posted clearly says otherwise - or at least the results of many other people's testing back up mine at the very least. I will check it out with a diffractin grating later today, but without an optical spectrum analyzer I don't know if I'll get very far.

I'll tell you this though - the visible emission of 808nm I see has the beam specs of the laser diode, not those of LED emission.

 

[Aseras]

Diode lasers emit 1 wavelength of light only. it may be +- 1-5 nm but it's only going to be within that range.

When you use say a 808 to pump a crystal however you can get other wavelengths depending on the harmonics of the crystal and the optical cavities. You can alter these to expand the trace lines and filter the 808 output, this is how most blue lasers are made and why they are so damn expensive and such low powers. they filter the primary emmision lines and use a trace line.

diodes are not full spectrum emitters. you can make hybrid diodes that emit a handful of frequencies, but it's not like filtering light with a prism. Sunlight has every wavelength there is, from radio to IR to visible light to uv, xray and gamma radiation and more. In fact it's quite possible there even lower and higher frequencies of EM radiation we cannot even detect.