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Prof. James Hammonds

Department of Physics & Astronomy, Howard University

 

Rescheduled to December 1, 3:30 PM

Thirkield Hall (Physics), room 103

 

Thermally Driven Sensitive Surface Phonon Polariton Modes in Thin-Film SiC

Surface phonon polaritons (SPhP) are interface restricted wave modes that do not usually participate in thermal radiative energy exchange.  In this talk, the possibility of varying the spectral properties by using a thin-film surface active material, layered between dielectrics, is explored.  Unlike surface gratings, the multilayered structure discussed in this talk couples the surface modes into radiative modes using subtle changes in refractive index.  The proposed multilayer effect is studied by first developing the SPhP mode dispersion relation to identify the spectral location of the surface modes. The relationship between SPhP coupling and refractive index change is then developed. The fluctuation-dissipation theorem and an impedance boundary condition is used to theoretically show how thermal radiation can excite SPhP modes. Results are then presented that show how film thickness and substrate properties act to support SPhP modes that are particularly sensitive to changes in refractive index changes and therefore offers opportunities for dramatic changes to thermal radiative spectral properties.

 

Refreshments will be served at 3:15 pm