Microholographic multilayer optical disk data storage

TLDR

Micrometer‑sized reflection holograms can be written into a rapidly rotating homogeneous photopolymer disk at the focus of a high‑numerical‑aperture beam and its retroreflection to implement high‑capacity multilayer digital data storage. The system uses a positive‑unity magnification optical setup to generate retroreflection for passive alignment, and this configuration was experimentally validated at 532 nm by writing and reading 12 microhologram layers in a 125‑µm photopolymer disk rotating at 3600 rpm. Analysis shows that the bit‑based holographic system achieves storage capacity and transfer rates comparable to traditional page‑based systems while reducing complexity and cost, and experimental results predict a capacity limit of 140 Gbytes in a millimeter‑thick disk or over 1 Tbyte using Blu‑Ray wavelengths and numerical aperture.

Abstract

Micrometer-sized reflection holograms can be written into a rapidly rotating homogeneous photopolymer disk at the focus of a high-numerical-aperture beam and its retroreflection to implement high-capacity multilayer digital data storage. This retroreflection is generated by an optical system with positive unity magnification to ensure passive alignment of the counterpropagating beam. Analysis reveals that the storage capacity and transfer rate of this bit-based holographic storage system compare favorably with traditional page-based systems but at a fraction of the system complexity and cost. The analysis is experimentally validated at 532 nm by writing and reading 12 layers of microholograms in a 125-microm photopolymer disk continuously rotating at 3600 rpm. The experimental results predict a capacity limit of 140 Gbytes in a millimeter-thick disk or over 1 Tbyte with the wavelength and numerical aperture of Blu-Ray.