High‐Efficiency Optical Filters Based on Nanophotonics

Abstract

Nanophotonic structures are artificial optical substances composed of structures smaller than incident light wavelengths. For example, it can artificially create a unique refractive index that is not found in substances in the natural world. That is, by designing the shape of the nanophotonic structure, an optical filter device that exhibits an optical response on demand can be realized. Also, we can realize applied devices with useful functions that cannot be realized by substances existing in nature, such as antireflective surfaces with 0% reflectance, wavelength-selective filters with 100% reflectance at specific wavelengths, and filters that shift the resonant wavelength in response to changes in the ambient refractive index. There can be applications to highbrightness light-emitting elements, high-efficiency power generation elements, color filters for full-color high-resolution cameras, miniature spectroscopic systems, high-efficiency biosensors, and so on. In the future, the development of further applications with this technology is widely expected in the fields of information, energy and global environment, and medical care and welfare. This paper describes high-efficiency optical filters based on nanophotonic technologies.