Imaging characteristics of the axicon imaging system

The depth of an image system can be extended by an axicon which can generate line focus. According to physical optical theory, the diffracting patterns of the defocus point spread function (PSF) for the imaging system with axicon are analyzed through the generalize pupil function. The expressions of the PSF for the imaging system illuminated by white light are described as the superposition of the intensities in individual monochromatic patterns. Experimental results show that the central portion contains the most energy of the diffraction pattern from the PSF produced by the white light, and the contrast of secondary outside circular rings decreased rapidly. Furthermore, the central spot radius varied slowly with the increase of defocus parameter, and the depth of field of the imaging system is effectively extended with a shortcoming that the images need further processing.