Broadband achromatic anomalous mirror in near-IR and visible frequency range

TL;DR

This paper presents a design for an achromatic mirror operating in near-IR and visible frequencies using MIM resonators, capable of steering incident beams with high efficiency and minimal losses.

Contribution

It introduces a novel broadband achromatic mirror design based on MIM resonators that achieves large deflection angles with high efficiency.

Findings

Achieves reflection angles up to 40° with high radiation efficiency.

Operates achromatically across near-IR and visible frequencies.

Maintains low Joule losses below 10%.

Abstract

The anomalous achromatic mirror operating in near-IR and visible frequency range was designed using an array of metal-insulator-metal (MIM) resonators. An incident wave interacting with MIM resonator experiences phase shift that is equal to the optical path travelled by the gap plasmon, excited by the wave. The phase gradient along the mirror surface is created through the difference in plasmons optical paths in resonators of different lengths. In the frequency region well below the plasma frequency of the metal, the phase gradient is a linear function of frequency, and thus the mirror operates in achromatic regime, i.e. reflection angle does not depend on the radiation frequency. Using silver-air-silver resonators, we predicted that the mirror can steer normally incident beam to angles as large as 40$^{\circ}$ with high radiation efficiency (exceeding 98 $\%$) and small Joule losses (below 10 $\%$).