[Mechanism of recording infrared radiation by the unaided human eye]

Results of experimental study of non-linear perception of IR-radiation within the range 1--1.5 mkm with man's naked eye are presented. It is shown that the region of non-linear perception is localized on molecules of the retina elements. It has been stated experimentally that radiation with the wave length 1 mkm is sensed simultaneously as red, green and yellow light. The shift of the wave length of perceived light relative to the 2nd harmonics of IR radiation is the value of the order +/- 10 nm and depends on radiation intensity. It has been stated that with an increase of radiation current density of the eye retina with the help of lenses the clearly seen colour image of the point is substituted by the perception without the expressed coloration.