Progress of super-resolution near-field structure and its application in optical data storage

The era of big data has necessitated the use of ultra-high density optical storage devices. Super-resolution near-field structure (super-RENS), which has successfully surpassed the fundamental optical diffraction limit, is one of the promising next generation high-density optical storage technologies. This technology combines the traditional super-resolution optical disk with a near-field structure, and has the advantages of structural simplicity, strong practicability, and, more importantly, compatibility with the current optical storage pickup. The mask layer in super-RENS functions as the key to realizing super-resolution. Development of suitable materials and stack designs has greatly been improved in the last decade. This paper described several types of super-RENS, such as aperture-type, light scattering center-type, bubble-type, and other types (e.g., WO x and ZnO), particularly the newly proposed super-RENS technology and research achievements. The paper also reviews the applications of super-RENS in high-density optical data storage in recent years. After analyzing and comparing various types of super-RENS technology, the paper proposes the aperturetype based on the mechanism of nonlinear optics as the most suitable candidate for practical applications in the near future.