Focusing Laser Light by Axicon and Zone Plate
This chapter analyzes the sharp focus of radially polarized laser light by means of microoptics. Axicons are known to be suitable for generating a diffraction-free laser Bessel beam in a definite range of the optical axis. The relation between the central peak diameter of the light field and the distance to the axicon should be similar to that between the axial intensity and the distance to the axicon. Axicons are known to be suitable for generating a diffraction-free laser Bessel beam at a certain optical axis segment. Light can be focused at a wavelength distance from the surface using a conventional binary zone plate (ZP) with the near-unity numerical aperture. The focusing of the Bessel–Gaussian beam with the aid of a ZP and an aplanatic objective was also simulated in Reference.