Fig. 5: Tracking the position of a light point source using the BAC-eye.

a Schematic diagram of the light point source tracking experiments. b The positions of the light spots. The yellow and green solid dots are the target and measured positions used for calibration, respectively. The yellow and green circles are the target and measured positions from experiments where the light location is not known a priori. c–e The light distribution collected by the BAC-eye and f–h the corresponding hemispherical images of the light spots at a radial distance 5, 7, and 9 mm away from the original point. Yellow dots are the average grayscale measured from the proximal ends of the waveguides. The colour scale represents the intensity level of the detected light. i The relation between the full width at half maximum (FWHM) of the light distribution obtained by the BAC-eye and the distance from the original point to the light spot. j The light distribution obtained for the light spot at a nominally-unknown position and k the corresponding hemispherical images of the light spot.