High-efficiency quasi–three-dimensional sub-wavelength structure devices (Invited Paper)

Optical coatings are enabling technology for modern optical systems, they are almost applied on every surface of the optical components. However, due to the uniform structure of the optical coatings, optical coatings have limited capability manipulating electromagnetic characteristics. Optical metasurfaces can locally manipulate optical field and enhance light–matter interactions, thus offering fascinating possibilities to control various properties of light, such as amplitude, phase, and polarization. While many new physical effects and applications were demonstrated based on metasurfaces, their practical application still faces challenges of low optical efficiency. Here, we propose the quasi-three-dimensional subwavelength structures, consisting of optical coatings and metasurfaces, to promote the efficiency of metasurfaces. We will present our recent advances in high-efficiency quasi-three-dimensional subwavelength structure devices. Our results pave the way to realizing optical meta-devices facing strict efficiency requirements in realistic applications.