Through simulations, this work explores the effects of conducting, semiconducting, and insulating substrates on the absorption of infrared radiation by radiative polaritons in oxide layers with thicknesses that range from 30 nm to 9 μm. Using atomic layer deposition, oxide layers can be formed in the nanometer scale. Our results suggest that the chemistry and conductivity of the substrate determine the amount of absorption by radiative polaritons in oxide layers thinner than the skin depth. The effects of the chemistry and conductivity of the substrate are especially effective for oxide films thinner than about 250 nm, which we label as the substrate sensitive thickness of the oxide film.
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http://dx.doi.org/10.1366/11-06489 | DOI Listing |
Discov Nano
January 2025
LIMMS, CNRS-IIS IRL 2820, The University of Tokyo, Tokyo, 153-8505, Japan.
We demonstrate unprecedented control and enhancement of thermal radiation using subwavelength conical membranes of silicon nitride. Based on fluctuational electrodynamics, we find that the focusing of surface phonon-polaritons along these membranes enhances their far-field thermal conductance by three orders of magnitude over the blackbody limit. Our calculations reveal a non-monotonic dependence of the thermal conductance on membrane geometry, with a characteristic radiation plateau emerging at small front widths due to competing effects of the polariton focusing and radiative area.
View Article and Find Full Text PDFACS Nano
January 2025
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Ultrafast thermal switches are pivotal for managing heat generated in advanced solid-state applications, including high-speed chiplets, thermo-optical modulators, and on-chip lasers. However, conventional phonon-based switches cannot meet the demand for picosecond-level response times, and existing near-field radiative thermal switches face challenges in efficiently modulating heat transfer across vacuum gaps. To overcome these limitations, we propose an ultrafast thermal switch design based on pump-driven transient polaritons in asymmetric terminals.
View Article and Find Full Text PDFNanoscale
December 2024
National Key Laboratory of Advanced Micro and Nano Fabrication Technology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Broadband metamaterial absorbers in the long wavelength infrared region are promising in applications including thermal imaging, cloaking, radiative cooling and IR signature suppression. Although high absorption over the long wavelength infrared region has been extensively achieved, the challenge is to shrink both the thickness and lateral footprint of unit absorbing structures. Here, a compact broadband long wavelength infrared metamaterial absorber consisting of multilayered Ge/Ti/Ge/SiO hybrid cylindrical structures, whose period and thickness are only ∼1.
View Article and Find Full Text PDFNanophotonics
June 2024
Materials Structural Dynamics Laboratory, Department of Chemistry, Wayne State University, 48202, Detroit, MI, USA.
It remains unclear how the collective strong coupling of cavity-confined photons to the electronic transitions of molecular chromophore leverages the distinct properties of the polaritonic constituents for future technologies. In this study, we design, fabricate, and characterize multiple types of Fabry-Pérot (FP) mirco-resonators containing copper(II) tetraphenyl porphyrin (CuTPP) to show how cavity polariton formation affects radiative relaxation processes in the presence of substantial non-Condon vibronic coupling between two of this molecule's excited electronic states. Unlike the prototypical enhancement of Q state radiative relaxation of CuTPP in a FP resonator incapable of forming polaritons, we find the light emission processes in multimode cavity polariton samples become enhanced for cavity-exciton energy differences near those of vibrations known to mediate non-Condon vibronic coupling.
View Article and Find Full Text PDFNanophotonics
August 2024
Univ Lyon, Ecole Centrale de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CPE Lyon, CNRS, INL, UMR5270, Ecully 69130, France.
Bound states in the continuum have recently been utilized in photonic crystal gratings to achieve strong coupling and ultralow threshold condensation of exciton-polariton quasiparticles with atypical Dirac-like features in their dispersion relation. Here, we develop the single- and many-body theory of these new effective relativistic polaritonic modes and describe their mean-field condensation dynamics facilitated by the interplay between protection from the radiative continuum and negative-mass optical trapping. Our theory accounts for tunable grating parameters giving full control over the diffractive coupling properties between guided polaritons and the radiative continuum, unexplored for polariton condensates.
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