Can the human eye detect infrared rays?

For the first time, an international team of scientists found that, under certain conditions, the human eye is able to detect “invisible” infrared rays.

The researchers used retinal cells from mice and humans and powerful lasers that emit pulses of infrared light.

Scientists found that when laser light pulses are generated faster, light-sensitive cells in the retina perceive infrared radiation as double.

When this happens, the human eye is able to pick up rays that fall outside the visible spectrum.

One of the scientists leading the team of researchers notes that efforts are currently being made to develop a new tool that will allow doctors not only to examine the eyes, but also to stimulate specific parts of the retina to determine if it is functioning properly.

The researchers began their study, due to the accounts of many specialists, because they saw a green light when working with infrared radiation.

Frans Winberg, one of the study’s lead authors, points out that during the study, his team was able to see the laser beams, which are normally outside the visible range.

The visible spectrum covers light waves with a length of 400 to 720 nanometers.

But if a retinal pigment molecule simultaneously captures a pair of 1000-nanometer photons, these light particles deliver the same amount of energy as one 500-nanometer photon, which is clearly visible in the visible spectrum in green color.

So actually we can see in the infrared spectrum.

The team of scientists experimented with laser pulses of different durations, keeping the number of photons they carry unchanged.

They found that the shorter the laser pulse, the more likely a person would be able to see it.

Normally, light particles /photons/ are absorbed by the retina, which then creates a molecule – a photopigment, which begins the process of converting light into vision.

In principle, each of the plurality of photopigments absorbs one photon.

With a special infrared laser generating pulses of shorter duration, ophthalmologists will be able to stimulate parts of the retina, thus making it easier to get to know its structure in healthy people and in those with diseases in this part of the eye.

The results of the study were published in the journal Proceedings of the National Academy of Sciences (PNAS)