Diffraction intensity distribution of an axicon illuminated by polychromatic light

A theoretical treatment is given for the diffraction intensity distribution of an axicon in polychromatic light illumination. Based on the dispersing theories of polychromatic light and the diffraction pattern of an axicon in monochromatic light illumination, the diffraction patterns of an axicon illuminated by a red high-brightness LED are derived. Experimental results show that the diffraction intensity in polychromatic light is a superposition of the intensities in individual monochromatic patterns. Furthermore, the central spot radius decreases with an increase in the distance l between the point source and the lens L, and the intensity of the central spot increases with an increase in l.