Rigorous vector analysis of diffractive micro-cylindrical lenses’characteristics of focal depth and focal shift

The vector diffraction characteristic must be considered to diffractive optical elements whose features are on the order of or smaller than the wavelength of the incident illumination. We present the rigorous vector analysis of diffractive micro cylindrical lenses that are finite in extent using a two-dimension finite-difference time-domain (FDTD) method. Using these effective analysis tools,lens' characteristics of focal depth and focal shifthave been analyzed rigorously. The results are compared with the scalar theory and the effects of quantified profiles are presented,respectively. Minimizing the numerical dispersion in the FDTD calculation region,setting the absorbing boundary and calculating the steady state electromagnetic fields' propagation from the FDTD region to the observation plane has been discussed in detail.