Wednesday, August 03, 2016

Single Photon Detection by Human Eye

Contrary to the common belief, a single photon perception by a human eye might be possible, says Nature Communications paper "Direct detection of a single photon by humans" by Jonathan N. Tinsley, Maxim I. Molodtsov, Robert Prevedel, David Wartmann, Jofre Espigulé-Pons, Mattias Lauwers and Alipasha Vaziri from University of Vienna, Austria.

From the abstract: "we report that humans can detect a single-photon incident on the cornea with a probability significantly above chance. This was achieved by implementing a combination of a psychophysics procedure with a quantum light source that can generate single-photon states of light. We further discover that the probability of reporting a single photon is modulated by the presence of an earlier photon, suggesting a priming process that temporarily enhances the effective gain of the visual system on the timescale of seconds."

Model for photon-induced priming of single-photon detection probability.


  1. I've seen material on this topic before, mostly: G. Field (see ref 4 etc)

    [ref 4] Field, G. D., Sampath, A. P. & Rieke, F. Retinal processing near absolute threshold: from behavior to mechanism. Annu. Rev. Physiol. 67, 491–514 (2005).

    It is an interesting topic, one that highlights a) the superb properties of biological eyes and b) shows the advantages of various network, thresholding and signal addition schemes shown in physiology.

    Very nice...

  2. maybe it's me, but I thought we've arrived at this some decades ago?

  3. Didn't Ernest Rutherford perform an extreme self-experiment to detect single photons? I heard of enclosing for days in an dark chamber and of pushing eye sensitivity by using Strychnine?? Can someone confirm this?

  4. I wondered why I could clearly perceive the scintillation glow of a small LYSO crystal, irradiated by a small lump of natural thorianite when placed right before my eye, myself prepared by sleeping a few hours before the test and preparing the setup for access in total darkness. My experimental cameras later had a hard time detecting this blue light. I have always doubted the six-photons-at-a-time threshold of the eye that I once learned at university. Now let's build a single-photon laser pointer and check out my cat's attention threshold :)


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