Optical data storage using diffractive optical elements

The diffractive optical element (DOE) can transform wavefront and generate arbitrary intensity distribution. In this study, we focus on these functions of DOE, and examined the possibility as read-only memory (ROM) usage of the DOE. The DOE based optical data storage is thought of as a kind of holographic data storage (HDS) using thin holograms. In the HDS, digital data is recorded and read out as modulated two-dimensional page data, instead of bit-by-bit recording in conventional optical disks. We design and optimize the DOE using the iterative method with regularization. In the design and optimization process, we use iterative Fourier transform algorithm that is known as Gerchberg-Saxton algorithm. Designed and optimized DOE is fabricated by ultraviolet (UV) nanoimprinting technology. By adopting nanoimprinting technology, high productivity can be expected. Fabricated DOE is evaluated in the experiment. We verify that DOE for optical data storage can be actualized.