In which color human eye is most sensitive?

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    $\begingroup$ An additional question: what is the quantum efficiency of the eye? $\endgroup$
    – nibot
    Jan 17, 2011 at 16:27

2 Answers 2


Around 555nm wavelength - green color. That's why green lasers are soo cool even at 10 mW :-D

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    $\begingroup$ you can put that link in a ![alt text](http://upload.wikimedia.org/wikipedia/commons/e/e9/Eyesensitivity.png) construct to have it shown here directly $\endgroup$ Jan 17, 2011 at 15:40

Answer to the additional question: "what is the quantum efficiency of the eye?" I remember old studies reporting that eight photons reaching the photoreceptors can be detected by a human observer as a flash of light in certain laboratory conditions. The more normal range would certainly be lower than 0.125 say 0.05 - 0.01. Cooling down laboratory animals thus reducing thermal noise in the retina enhances sensitivity but means longer integration times and lower spatial and temporal resolution.

  • $\begingroup$ A little late to the party, but this is a nice article that explains those studies and has the references: desy.de/user/projects/Physics/Quantum/see_a_photon.html $\endgroup$
    – Arnoques
    Nov 26, 2011 at 5:03
  • $\begingroup$ Cooling down laboratory animals? How did they survive that to be able to actually see? And, BTW, how did they report the flashes they saw? $\endgroup$
    – Ruslan
    Dec 27, 2020 at 18:22

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