Optimal design of photon-sieve holograms for fine-line image generation

Abstract

A photon-sieve hologram (PSH) is a computer-generated hologram that can generate fine-line images. As a high-resolution image can be projected directly without using a reducing optical system, it can also be used for short-wavelength radiation, such as X-rays. We propose an optimum design method for the PSH so that a high-quality line image can be projected. We optimised straight-line and L-shaped bent-line images using numerical simulation based on vector diffraction theory and conjugate-gradient methods. This optimisation helped homogenise the intensity of the image and remove unwanted side lobes and spots around the image. We also experimentally examined the bent-line image before and after the optimisation to confirm its effect.