Probing Near-Field Thermal Emission of Localized Surface Phonons from Silicon Carbide Nanopillars

Abstract

Thermal emission of localized surface phonons (LSPhs) from nanostructures of polaritonic materials is a promising mechanism for tuning the spectrum of near-field thermal radiation. Previous studies have theoretically shown that thermal emission of LSPhs results in narrow-band peaks in the near-field spectra, whose spectral locations can be modulated by changing the dimensions of the nanostructure. However, near-field thermal emission of LSPhs has not been experimentally explored yet. In this study, we measure the spectrum of near-field thermal radiation from arrays of 6H-silicon carbide (6H-SiC) nanopillars using an internal-reflection-element based spectroscopy technique. We present an experimental demonstration of thermal emission of the transverse dipole, quadrupole, and octupole as well as longitudinal monopole from 6H-SiC nanopillars at a near-field distance from the array. We show that the spectral locations of the longitudinal monopole and transverse dipole are significantly affected by the near-field coupling between neighboring nanopillars as well as the intercoupling of the nanopillars and the substrate. We also experimentally demonstrate that the spectrum of near-field thermal radiation from 6H-SiC nanopillar arrays can be tuned by varying the dimensions of the nanopillars, providing an opportunity for designing emitters with tailored near-field thermal radiation.

Tunable infrared surface phonon–plasmon coupling in graphene-integrated polar semiconductor heterostructure

“…Here, the information transmission of molecular vibrations and blackbody radiation is transparent and frequently used for material phase and spatial target identifications, respectively. With a strong field confinement, the surface phonon technology has been developed for a variety of thermal radiation applications, [11][12][13][14] and the polar crystals are potential in active photonic devices as well. 15,16 Controllable interplay of different electromagnetic resonant modes is a distinct recent interest in optical metasurfaces, especially the surface phonon-plasmon coupling.…”