Ultrabroadband Perfect Reflectors by All-Dielectric Single-Layer Super Cell Metamaterial

All-dielectric metamaterials (MMs) realize low-loss high efficiency reflector by utilizing Mie resonances in high-permittivity resonators. A single-negative all-dielectric near-perfect reflector is realized by a single layer of silicon (Si) cylinder resonators MM. The average reflection over 99% across 150.6-nm wide bandwidth in near infrared wavelength is achieved. Ultrabroadband perfect reflector was proposed by all dielectric single-layer super cell MM. It consists of four Si nanocylinders with different radius in single unit cell, which possesses peak reflection over 99% and a 313.3 nm wide near-perfect reflection (>95%) bandwidth. In order to achieve the required reflection bandwidth, we controlled the spectral separation of the electric and magnetic resonances.