Lensless Optical System for Fabricating Holographic Photonic Crystal

A compact lensless optical system is proposed in the paper, in order to generate the mask with 2-dimensional hexagonal lattice used for photonic crystal fabrication. The key element in the system is a holographic optical element consisting of three symmetrically arranged holograms. Under the illumination of a spherical wave, the element can generate three plane waves to form uniform hexagonal lattice pattern with large size. The technique is suitable for industrial applications to achieve fast and mass production of photonic crystals in semiconductor materials.