The research was initiated after scientists on the research team reported seeing occasional flashes of green light while working with an infrared laser. Unlike the laser pointers used in lecture halls or as toys, the powerful infrared laser the scientists worked with emits light waves thought to be invisible to the human eye.

But packing a lot of photons in a short pulse of the rapidly pulsing laser light makes it possible for two photons to be absorbed at one time by a single photopigment, and the combined energy of the two light particles is enough to activate the pigment and allow the eye to see what normally is invisible.

“The visible spectrum includes waves of light that are 400-720 nanometers long,” explained Kefalov, an associate professor of ophthalmology and visual sciences. “But if a pigment molecule in the retina is hit in rapid succession by a pair of photons that are 1,000 nanometers long, those light particles will deliver the same amount of energy as a single hit from a 500-nanometer photon, which is well within the visible spectrum. That’s how we are able to see it.”

Neat! But please don't shine lasers into your eyes even if it's supposed to be invisible.

[–] [email protected] -1 points 9 months ago

Also, isn't it wildly known that some people see some shades of infra rouge?

[–] [email protected] 22 points 9 months ago* (last edited 9 months ago) (2 children)

I've always been able to see the IR light from those depth sensing cameras used for facial recognition on laptops, as well as those sensors old android phones used to use to detect if they're face down on a table or up to your ear.

It just looks like dark red to me. My science teacher in highschool told me it's not common but some people have a wider spectrum of light thats visible to them than others. This special gift from nature has not meaningfully impacted my life in any way, shape, or form.

[–] Zikeji 12 points 9 months ago (2 children)

I had just assumed those were supposed to be visible. Like the lights the Xbox Kinect had.

But if they aren't, that's annoying lol. Same deal with hearing the high pitch frequency old CRTs would emit.

[–] [email protected] 16 points 9 months ago (3 children)

The CRT thing is pretty common I think, you just lose your high frequency hearing as you age.

[–] [email protected] 14 points 9 months ago (1 children)

The high pitch squeals just move to inside your head.

[–] [email protected] 4 points 9 months ago

Ugh this has become very true as I’ve aged :’(

[–] [email protected] 3 points 9 months ago

I lost it at a Cypress Hill concert

[–] Zikeji 2 points 9 months ago

Yeah, I was using it as an example of annoying things fitting around the same niche lol.

[–] [email protected] 3 points 9 months ago

Its not intentional as much as it is a cost savings

[–] [email protected] 6 points 9 months ago

Thats mostly because the vast majority of IR lights and led's also emit visable light. To get an ir light to not also emit within the visable light spectrum is much more expensive.

[–] [email protected] 7 points 9 months ago

I can barely see normal visible red.

Stupid Deuteranomaly

https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/color-blindness/types-color-vision-deficiency

[–] [email protected] 3 points 9 months ago (1 children)

Do you suppose the green flash phenomenon should be revisited? A combo of light, atmosphere and the human eye seems reasonable to me.

[+] [email protected] 6 points 9 months ago* (last edited 8 months ago) (1 children)

[removed by mod]

[–] [email protected] -2 points 9 months ago (1 children)

What does being able to capture it on film have to do with it?

[–] [email protected] 3 points 9 months ago (1 children)

When you take a photo, your eyes are not involved (apart from setting up the camera). The light comes from the source and goes through the camera lens onto the film or camera sensor, your eyes are not a factor at that point.

[–] [email protected] -2 points 9 months ago

Yes in a vacuum where you are only trying to capture a pinpoint light source. The sun is many orders of magnitude greater and refracted through an atmosphere of gas, water molecules and dust. Are you saying none of these are factors in the ability for a camera to capture what the human eye can only observe in very specific circumstances? If I’m still wrong, please explain yourself better than just basic information on how a camera works.