Open AccessVision with pulsed infrared light is mediated by nonlinear optical processes
Author(s) -
Silvestre Manzanera,
D. Sola,
Noe Khalifa,
Pablo Artal
Publication year - 2020
Publication title -
biomedical optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.403695
Subject(s) - optics , infrared , stimulus (psychology) , nonlinear system , wavelength , photon , physics , spectral sensitivity , nonlinear optics , laser , psychology , quantum mechanics , psychotherapist
When the eye is exposed to pulsed infrared (IR) light, it is perceived as visible of the corresponding half wavelength. Previous studies have reported evidence that this is due to a non-linear two-photon absorption process. We have carried out a study which provides additional support to this nonlinear hypothesis. To this end, we have measured the spectral sensitivity at 2 different pulse repetition rates and have developed a theoretical model to account for the experimental observations. This model predicts a ratio between the minimum powers needed to detect the visual stimulus at the 2 pulse repetition rates employed of 0.45 if the stimulus were detected through a nonlinear effect and 1 if it were caused by a linear effect as in normal vision. The value experimentally found was 0.52 ± 0.07, which supports the hypothesis of a nonlinear origin of the two-photon vision phenomena.