Tunable VO2 cavity enables multispectral manipulation from visible to microwave frequencies

Abstract

Optical materials capable of dynamically manipulating electromagnetic waves are an emerging field in memories, optical modulators, and thermal management. Recently, their multispectral design preliminarily attracts much attention, aiming to enhance their efficiency and integration of functionalities. However, the multispectral manipulation based on these materials is challenging due to their ubiquitous wavelength dependence restricting their capacity to narrow wavelengths. In this article, we cascade multiple tunable optical cavities with selective-transparent layers, enabling a universal approach to overcoming wavelength dependence and establishing a multispectral platform with highly integrated functions. Based on it, we demonstrate the multispectral (ranging from 400 nm to 3 cm), fast response speed (0.9 s), and reversible manipulation based on a typical phase change material, vanadium dioxide. Our platform involves tandem VO2-based Fabry–Pérot (F-P) cavities enabling the customization of optical responses at target bands independently. It can achieve broadband color-changing capacity in the visible region (a shift of ~60 nm in resonant wavelength) and is capable of freely switching between three typical optical models (transmittance, reflectance, and absorptance) in the infrared to microwave regions with drastic amplitude tunability exceeding 0.7. This work represents a state-of-art advance in multispectral optics and material science, providing a critical approach for expanding the multispectral manipulation ability of optical systems.

Evolution and Combination of Light Line Singularities in Planar Multilayers

“…Although TPSP can achieve a high Q -factor perfect absorption, they can only be manipulated by changing the material parameters, which is not convenient for applications. Recently, some excellent works have been reported about dynamic control using graphene, − liquid crystal, − phase-change materials, − and other nondestructive methods. Therefore, we explore a strategy to dynamically manipulate the positions of these high- Q TPSPs in the ω–θ plane, making them move to near BICs or light line singularities to control the magnitude of the Q factors.…”