Tunable Multi-Peak Perfect Absorbers Based on Borophene for High-Performance Near-Infrared Refractive Index Sensing

TL;DR

This paper proposes borophene-based multi-peak perfect absorbers with high sensitivity for near-infrared refractive index sensing, demonstrating tunability and high performance through optimized design and simulations.

Contribution

It introduces a novel multi-peak borophene absorber design with tunable peaks and high sensitivity, advancing the reliability of near-IR refractive index sensors.

Findings

Achieved three near-IR absorption peaks with over 98% intensity.

Sensitivity of peaks up to 738.1 nm/RIU.

Tunable peaks via external electric bias.

Abstract

Borophene has recently attracted significant attention as an emerging two-dimensional monoelemental material for refractive index sensing because of its ultra-high surface-to-volume ratio and outstanding surface sensitivity. However, current research mainly focuses on designing borophene-based sensors with single-peak absorption, which lacks reliability compared to the performance of multi-peak sensors. In this paper, high-performance borophene refractive index sensors with multiple nearly perfect absorption peaks are proposed. The geometric parameters of the metadevices are optimized using finite-difference time-domain (FDTD) simulations to obtain three strong absorption peaks in the near-infrared (near-IR) regime with intensities of 99.72%, 99.18%, and 98.13%. Further calculations show that the sensitivities of the three strong peaks reach 339.1 nm shift per refractive index units (nm/RIU), 410.1 nm/RIU, and 738.1 nm/RIU, and their corresponding figure of merits (FOMs) reach up to 15.41/RIU, 14.65/RIU and 10.85/RIU, respectively, exhibiting great potential for near-IR refractive index sensing. Moreover, the three absorption peaks can be easily tuned by adjusting the carrier density of borophene, which can be realized by applying different external electric bias voltages. These results can provide theoretical guidance for the development of multi-peak near-IR dynamic integrated photonic devices