2020/01/12 by Vahid Hatamipour, Hatamipour, Vahid, Mathieu Francoeur +1
Engineering · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Computational Physics (physics.comp-ph) #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Optical properties and cooling technologies in crystalline materials #Optics (physics.optics) #Thermal Radiation and Cooling Technologies
paper · pdf · doi:10.48550/arxiv.2001.03999
openalex publication_date 2020/01/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A general formulation for the cross-spectral density tensor enabling\ncalculation of the spatial correlation of the thermally generated\nelectromagnetic field in layered media is derived. The formulation is based on\nfluctuational electrodynamics, and is thus applicable in the near and far field\nof heat sources. The resulting cross-spectral density tensor is written in\nterms of a single integration over the parallel wavevector, as the angular\nintegrations leading to numerical instability are evaluated analytically. Using\nthis formulation, the spatial correlation length in the near field of a film\nmade of silicon carbide (SiC) supporting surface phonon-polaritons (SPhPs) in\nthe infrared is analyzed. It is shown that the spatial correlation length of a\nSiC heat source suspended in vacuum decreases substantially by decreasing its\nthickness owing to SPhP coupling. In the limit of a 10-nm-thick SiC film, the\nspatial correlation length is similar to that of a blackbody. The results also\nreveal that it is possible to control the spatial coherence of a thin SiC heat\nsource via dielectric and metallic substrates, respectively allowing and\npreventing SPhP coupling. This suggests that active modulation of thermal\nemission via thin films supporting surface polaritons in the infrared is\npossible by using a phase change material substrate such as vanadium dioxide.\n