In the era of information explosion, the demand of data storage is increased dramatically. Holographic data storage technology is one of the most promising next-generation data storage technologies due to its high storage density, fast data transfer rate, long data life time and less energy consumption. Collinear holographic data storage technology is the typical solution of the holographic data storage technology which owns a more compact, compatible and practical system. This paper gives a brief review of holographic data storage, introduces collinear holographic data storage technology and discusses phase modulation technology being used in the holographic data storage system to achieve higher storage density and higher data transfer rate.

Electronic skin, a class of wearable electronic sensors that mimic the functionalities of human skin, has made remarkable success in applications including health monitoring, human-machine interaction and electronic-biological interfaces. While electronic skin continues to achieve higher sensitivity and faster response, its ultimate performance is fundamentally limited by the nature of low-frequency AC currents. Herein, highly sensitive skin-like wearable optical sensors are demonstrated by embedding glass micro/nanofibers (MNFs) in thin layers of polydimethylsiloxane (PDMS). Enabled by the transition from guided modes into radiation modes of the waveguiding MNFs upon external stimuli, the skin-like optical sensors show ultrahigh sensitivity (1870 kPa^-1), low detection limit (7 mPa) and fast response (10 μs) for pressure sensing, significantly exceeding the performance metrics of state-of-the-art electronic skins. Electromagnetic interference (EMI)-free detection of high-frequency vibrations, wrist pulse and human voice are realized. Moreover, a five-sensor optical data glove and a 2×2-MNF tactile sensor are demonstrated. These initial results pave the way toward a new category of optical devices ranging from ultrasensitive wearable sensors to optical skins.

This paper reviews the science of the optical near-field (ONF), which is created and localized in a nanometer-sized material (NM) or on its surface. It is pointed out that work on near-field optics was started in order to break through the diffraction limit in optical microscopy and had already come to an end without giving answers to the essential questions on the origin of the near-field optical interaction. However, recent studies have reincarnated these studies and identified the ONF as an off-shell quantum field. Based on this identification, a novel science called off-shell science has started on the basis that the dispersion relation between energy and momentum is invalid for the ONF. This quantum field is called the dressed photon because it is created as a result of the interaction between photons and electrons (or excitons) in a NM and, thus, it accompanies the energies of electrons or excitons. In reviewing current developments, this paper presents fifteen novel phenomena that are contrary to the common views in conventional optical science. Novel technologies developed by applying these phenomena are also reviewed. These include: nanometer-sized optical devices, nano-fabrication technology, and energy conversion technology. High-power Si light emitting diodes, Si lasers, and SiC polarization rotators are reviewed as examples of electrical to optical energy conversion. For future directions, this paper also reviews novel theoretical studies that have commenced recently by relying on physical and mathematical bases.