Ability to detect smallest unit of light focuses debate on vision sensitivity
Human eyes are capable of detecting a single photon — the tiniest possible speck of light — new research suggests.
The result, published July 19 in Nature Communications, may settle the debate on the ultimate limit of the sensitivity of the human visual system, a puzzle scientists have pondered for decades. Scientists are now anticipating possibilities for using the human eye to test quantum mechanics with single photons.
Researchers also found that the human eye is more sensitive to single photons shortly after it has seen another photon. This was “an unexpected phenomenon that we just discovered when we analyzed the data,” says physicist Alipasha Vaziri of Rockefeller University in New York City.
Previous experiments have indicated that humans can see blips of light made up of just a few photons. But there hasn’t been a surefire test of