Fano resonance in a dolomite phase-change multilayer design for dynamically tunable omnidirectional monochromatic thermal emission

Abstract

In this Letter, we unveil the unprecedented optical phonon response of CaMg(CO3)2 (dolomite) thin film in the design of a planar ultra-narrowband mid-infrared (MIR) thermal emitter. Dolomite (DLM) is a carbonate mineral composed of calcium magnesium carbonate, which can inherently accommodate highly dispersive optical phonon modes. Utilizing strong interference in the Al-DLM bilayer, a lithography-free planar thermal emitter is realized with near-unity omnidirectional emission at a specific resonance wavelength of 7.12 µm. Further incorporation of embedded vanadium dioxide (VO2) phase change material (PCM) enables the excitation of hybrid Fano resonances with dynamic spectral tunability. The findings of this study can have multiple applications, ranging from biosensing and gas sensing to thermal emission.

Phase-change Fano resonator for active modulation of thermal emission

“…However, this design cannot satisfy the spectral tunability requirements to achieve radiative cooling and thermal camouflage performance transformation. Therefore, a hybrid Fano resonator [34][35][36][37] is proposed, where the narrowband SmNiO 3 nanograting antenna (discrete level) is strongly coupled into a broadband Fabry-Perot (FP) resonator (continuum). Using theoretical modeling based on the transfer matrix method (TMM), it is found that the FP resonator gradually transforms from a perfect absorber host into a partially reflecting mirror upon temperature modulation.…”

Microheater-Integrated Spectrally Selective Multiband Mid-Infrared Nanoemitter for On-Chip Optical Multigas Sensing

“…Hexagonal boron nitride (hBN) is one such polar material having a very smooth surface and unique dielectric constant, which received significant interest due to its hyperbolic dispersion relation and ability to support hyperbolic PhPs. − However, these modes cannot be directly excited by the incidence of EM waves from the free space due to the large transversal wavenumber of these modes compared to the photon wavenumber in the free space . To achieve PhP resonance, − a conventional method is to place an hBN film over a deep metal grating, which also supports a particular type of localized polariton resonance known as magnetic polaritons (MPs). , Alternatively, the strong coupling of optical phonons (OPhs) can be achieved in a relatively easier way through the direct illumination of EM waves. , Therefore, hybrid structures of polar materials and metasurfaces have been widely utilized to create perfect or multiband absorption responses. For example, coupling MPs in metal gratings with PhPs in hBN creates hybrid hyperbolic phonon–plasmon polaritons that result in perfect or near-perfect MIR absorption .…”

“…23,24 Alternatively, the strong coupling of optical phonons (OPhs) can be achieved in a relatively easier way through the direct illumination of EM waves. 17,25 Therefore, hybrid structures of polar materials and metasurfaces have been widely utilized to create perfect or multiband absorption responses. For example, coupling MPs in metal gratings with PhPs in hBN creates hybrid hyperbolic phonon−plasmon polaritons that result in perfect or near-perfect MIR absorption.…”

Machine learning enabled rational design for dynamic thermal emitters with phase change materials

“…designed an Al/VO 2 /Dolomite multilayered film to generate hybrid Fano resonances, realizing a temperature-dependent near-unity narrowband emission, which might be a promising alternative for the temperature or biochemical sensors. 25 Hu et al. demonstrated a spatiotemporal modulation platform based on thermal hysteresis emission characteristics of VO 2 phase-change materials, which achieved various thermotronic functionalities including negative-differential thermal emission, thermal diodes/transistors, and provided a unique perspective for dynamic thermal management.…”