Focusing properties of two types of diffractive photonic crystal lens

We designed novel two type of binary 2D subwavelength (wavelength was λ= 10 mm) focus diffractive photonic crystal lens and calculated the diffraction of plane TE-wave by use FDTD-method (our program in C++). It has been shown that diffractive photonic crystal lens designs have not an unique solution. It has been also shown the diffractive lens with equal holes in Fresnel zones has better focusing characteristics. Lens diameter was 5 times more than her width and full width half maximum diameter of focal spot was 0.48λ.