# A simple metamaterial absorber associated with Fano-like resonance

## TL;DR

This paper introduces a scalable, simple metamaterial absorber leveraging Fano-like resonance, achieved through layered structures that allow spectral tuning via layer thickness control, simplifying fabrication over large areas.

## Contribution

The novel design enables spectral tuning of the metamaterial absorber by adjusting layer thicknesses, avoiding complex micro-structuring processes typical in conventional designs.

## Key findings

- Resonance arises from interference of cavity and guided modes.
- Spectral position can be tuned by layer thickness, not structural shape.
- Design simplifies fabrication for large-area applications.

## Abstract

A simple metamaterial absorber suitable for fabrication over large areas associated with a Fano like resonance is proposed. The proposed designed of the metamaterial absorber consists of photoresist disk arrays on a silicon substrate followed by the deposition of a tri layer of Au, ZnS and Au on the top of the structure. Due to the tri layer, there is a formation of a cavity between the substrate and gold layer on the top of photoresist disk and a waveguide in the ZnS layer in between the gold layers on the substrate and the ZnS layer itself. The Fano like resonance arises due to the interference of the cavity mode and the guided-mode resonance as well as the Woods anomaly. The cavity mode resonance works as continuum mode whereas the guided mode resonance and Woods anomaly work as discrete modes. The spectral position of the resonance can be tuned by just controlling the thickness of the tri layer instead of the structural size and shape modification of the micro and nano-structures as usually done in conventional metamaterial absorbers. This design can be easily scaled for fabrication over large areas as it separates the structuring and deposition processes and makes them sequential thereby avoiding expensive and complex lift off or etching processes which are usually required for conventional metamaterial processing.