Light is reflected at the interface between heterogeneous media due to the mismatch of impedance 1-3 . Removing this mismatch using additional materials, a technique known as anti-reflection, has so far been restricted to specific frequencies and incidence angles 3-7 . The anti-reflection of white light, which requires the simultaneous matching of impedance over extremely wide angular and spectral ranges, has until now been considered impossible. Here, we develop a theory of universal impedance matching and introduce a matching layer that enables the perfect transmission of white light. The ability of a matching layer to assist in omnidirectional and frequency-independent anti-reflection has been confirmed analytically and numerically. We explain the feasibility of a universal matching layer using metamaterials, and demonstrate a transmission rate of over 99% for white light in the visible range with a double-layered dielectric metamaterial. This is confirmed experimentally by demonstrating the omnidirectional anti-reflection of microwaves in heterogeneous media.
Bibliographical noteFunding Information:
This work was supported by the Samsung Science and Technology Foundation under project no. SSTF-BA1401-05. Q.-H.P. thanks Y. Kivshar and W. Choi for comments and encouragement.
© 2018 The Author(s).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics