In a recent study published in Engineering, researchers have introduced a novel concept called hybrid-layer optical data storage (ODS), which could potentially revolutionize the field of data storage.
As the digital age progresses, the demand for high-capacity data storage has surged. However, current ODS technologies, such as CDs, DVDs, and Blu-ray discs, have limited storage densities. To address this issue, the research team proposed a new approach that uses high-orthogonality random meta-channels to encode data into both physical and virtual layers.
The hybrid-layer ODS concept is based on metasurfaces, which can enhance the spatial resolution of the physical layer and reconstruct virtual layers through phase modulation. The physical layer is divided into multiple orthogonal channels, each encoding a unique pattern. By addressing these channels, holographic images can be reconstructed in the virtual layers.
To reduce crosstalk between stored images, the channels are designed with high spatial orthogonality and randomly distributed apertures. This is achieved through three main strategies: ensuring no spatial overlap between pixels in different channels, randomly locating pixels within each channel to avoid high-order diffractions, and encoding a holographic phase in each pixel to guide light for interference.
In the experiment, the researchers fabricated geometric metasurfaces using c-Si nanobricks. They were able to store a total of 48 images, including 16 printed images in the physical layer and 32 holographic images in the virtual layer. The achieved storage density was 2.5 Tbit cm⁻³.
Although the current capacity is not as high as some other methods, the researchers believe it can be significantly enhanced by increasing the number of virtual layers. They also simulated the feasibility of using more virtual layers and proposed methods to further improve the technology, such as introducing orthogonality into the holographic layers.
The hybrid-layer ODS concept shows great promise for future high-capacity data storage. By leveraging the unique properties of metasurfaces and holography, this approach could provide a more efficient and scalable solution to meet the ever-growing data storage needs.
The paper "Hybrid-Layer Data Storage with High-Orthogonality Random Meta-Channels," authored by Dong Zhao, Hongkun Lian, Xueliang Kang, Kun Huang. Full text of the open access paper: https://doi.org/10.1016/j.eng.2024.10.014
