Quantum optics used to measure human eye sensitivity

Daniel F. Walls, Gerard J Milburn

Rita M.R. Pizzi, Rui Wang, Danilo Augusto de Albuquerque Rossetti

This paper describes a computational approach to the theoretical problems involved in the Young's single-photon double-slit experiment, focusing on a simulation of this experiment in the absence of measuring devices. Specifically, the human visual system is used in place of a photomultiplier or similar apparatus. Beginning with the assumption that the human eye perceives light in the presence of very few photons, we measure human eye performance as a sensor in a double-slit one-photon-at-a-time experimental setup. To interpret the results, we implement a simulation algorithm and compare its results with those of human subjects under identical experimental conditions. In order to evaluate the perceptive parameters exactly, which vary depending on the light conditions and on the subject's sensitivity, we first review the existing literature on the biophysics of the human eye in the presence of a dim light source, and then use the known values of the experimental variables to set the parameters of the computational simulation. The results of the simulation and their comparison with the experiment involving human subjects are reported and discussed. It is found that, while the computer simulation indicates that the human eye has the capacity to detect the corpuscular nature of photons under these conditions, this was not observed in practice. The possible reasons for the difference between theoretical prediction and experimental results are discussed.

Gabriele Bizzarri, Assunta Di Vizio, Matteo Rosati +2 more

The evolving understanding of the limits of human visual perception has advanced the development of optical devices that not only correct visual defects but also help manage changes in certain eye structures. As modern optical technologies allow precise control of the quantum properties of light, recent endeavours have started testing the quantum capabilities of human eye perception, proving that they can detect single photons. This paves the way for the application of quantum metrology and cryptography to medical imaging, with potential increase in precision and security.

S. Chua

Juan F. Hodelin

Nicolas Brunner, Cyril Branciard, Nicolas Gisin

The human eye can detect optical signals containing only a few photons. We investigate the possibility to demonstrate entanglement with such biological detectors. While one person could not detect entanglement by simply observing photons, we discuss the possibility for several observers to demonstrate entanglement in a Bell-type experiment, in which standard detectors are replaced by human eyes. Using a toy model for biological detectors that captures their main characteristic, namely, a detection threshold, we show that Bell inequalities can be violated, thus demonstrating entanglement. Remarkably, when the response function of the detector is close to a step function, quantum nonlocality can be demonstrated without any further assumptions. For smoother response functions, as for the human eye, postselection is required.