Design and fabrication of diffractive optical elements with complex profile by interference

Abstract

A novel method is presented for the design and the fabrication of the Diffractive Optical Elements (DOEs) with arbitrary complex phase profile based on interference. The DOEs are designed to modulate the complex light wave by the analytical formulas, and asymmetric holographic DOE with cubic phase modulation is fabricated by two-step exposure technique on flat plane. Further it is employed for the modulation of the optical intensity on curved surfaces (CS) and apply it to fabricate diffractive optical elements (DOEs) with arbitrary profile and large area on CS. Both a binary pattern and a gray pattern are reconstructed numerically on the lens surfaces with big curvatures in large areas, while a binary and nonperiodic pattern is produced experimentally. The simulations together with the experiment demonstrate the validity of the method. It is believed that micro- or nano- optical elements with smaller feature sizes can be fabricated by the proposed method when an optical microscopy system is used. It will be a very efficient and convenient way to design and fabricate the DOEs with required complex fine structure.