Focal Depth of an Apodized Focusing Optical System

In this paper, the axial intensity distribution and focal depth of an apodized focusing optical system are theoretically investigated with uniform-intensity-distribution beam. The low numerical-aperture optical system is considered in the investigation. Numerical results show that the depth of focus can be adjusted by changing geometrical parameters and transmissivity of the apodizer contained in the focusing optical system. The tunable range of the focal depth is very considerable.