Telecom-band coherent perfect absorption and asymmetric interferometric light-light control in a borophene-dielectric...

Area of Science:

• Nanophotonics
• Materials Science

Background:

• Efficient electromagnetic absorption is crucial for optical modulation and integrated photonic devices.
• Interference-assisted resonant nanostructures can significantly enhance absorption.
• Borophene, a 2D material, offers unique electronic and optical properties.

Purpose of the Study:

• To propose and investigate a borophene-dielectric nanostructure for tunable coherent perfect absorption (CPA) at telecommunication wavelengths.
• To explore the mechanisms of guided-mode resonances (GMRs) and near-field enhancement in the nanostructure.
• To demonstrate electrical tunability of absorption and optical switching capabilities.

Main Methods:

• Fabrication of a borophene-dielectric nanostructure.
• Optical characterization under single-port and dual-port coherent excitation.
• Analysis of absorption spectra, resonance shifts, and scattering matrix.
• Investigation of electrical tuning of borophene carrier concentration.

Main Results:

• Achieved resonance-enhanced absorption with directional asymmetry (42.5% and 57.4%).
• Demonstrated CPA with a narrow bandwidth (0.82 nm) at 1549.8 nm.
• Showcased continuous absorption tuning from 10% to over 99.9% by adjusting phase difference.
• Observed a 12.4 nm resonance shift via electrical tuning, maintaining high absorption.

Conclusions:

• The proposed borophene-dielectric nanostructure provides a compact platform for phase-controlled absorption.
• The device enables efficient light-matter interaction and tunable optical switching.
• This work paves the way for advanced integrated photonic systems with tailored absorption properties.