Extending Human Vision to Infrared and Ultraviolet Light: A Study Using Micro-Particles and Fluorescent Molecules

In this study, rare earth doped infrared (IR) to visible, up-converting particles along-with efficient ultraviolet (UV) to visible fluorescent molecules were imbedded in proteins and were used as a mean for increasing the human vision range to infrared and ultraviolet wavelengths. Stilbene-420 fluorescent molecules which convert near UV light to blue light, were chosen for the strong overlap of their fluorescence emission with the sensitivity region of blue cone cells and for the ability of blue light to increase the regeneration of bleached visual pigments. Our data show that the up-conversion efficiency of the IR up-converting particles and blue fluorescing molecules efficiencies remained unchanged when these material are imbedded in proteins compared to their efficiencies in water solutions. Addition of up-converting particles to rod visual cells resulted in the bleaching of the visual pigments, rods, when irradiated with infrared light (980 nm) whereas no bleaching was observed, under the same conditions, without the presence of up-converting particles. This suggests that the up-converted green light induced visual process in the rod visual pigments. In addition, we describe the design and present data of a novel optical device, which can be used as eye glasses, utilizing up-converting particles that allows the wearer to see rather intense infrared light.