Compact phase-change multilayer architecture for dynamically tunable ultrabroadband near-perfect absorption

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Conventional Fabry-Pérot absorbers face inherent trade-offs between bandwidth, efficiency, and tunability.
• Achieving broadband, high-efficiency, and reconfigurable absorbers simultaneously has been a significant challenge.

Purpose of the Study:

• To report a novel asymmetric, high-loss, cascaded Fabry-Pérot ultracompact cavity.
• To overcome the intrinsic limitations of conventional absorbers and enable versatile applications.

Main Methods:

• Fabrication of a single planar, lithography-free stack comprising an engineered, multi-material structure.
• Utilizing reversible crystallization of AIST (Amorphous Indium-Antimony-Telluride) layers to modulate refractive index.
• Incorporating a graded-index antireflection scheme to enhance performance.

Main Results:

• Achieved ultrabroad spectral coverage from 380-2500 nm.
• Demonstrated ~97% band-averaged absorptance with a 147% relative bandwidth.
• Exhibited dynamic tunability with up to ~30% absorption-contrast modulation in the short-wave infrared band.
• Maintained polarization-independent absorption for incidence angles up to 70°.

Conclusions:

• The developed platform offers a manufacturable, scalable solution for broadband, tunable light absorption.
• Potential applications include multispectral camouflage, adaptive thermal control, energy conversion, and stealth technologies.