Physics Chat
Effects of electronic interband transition on Transverse-electric transmission in graphene grating
Speaker: Zeeshan Ahmad (Sang Soon Oh's group)
Date: Thursday 1 December 2022
Time: 14:00
Venue: Queen's building WX3.07 with zoom live streaming
Photonic devices where the permittivity is almost frequency-independent but periodic in space are commonly used in controlling the flow of electromagnetic waves and providing coupling to guided modes. A plethora of devices based on photonic crystals have emerged, for example, polarizers, waveguide splitters and filters. The optical properties of these systems fundamentally change when the permittivity becomes frequency-dependent by replacing some dielectric parts in the structure with conductors having a highly dispersive optical conductivity. Bragg scattered electromagnetic waves couple to mobile charges in the conductor parts of the system, such as metal or graphene, forming surface plasmons. This opens up a new avenue to subwavelength confinement of light, and thus possibilities for designing plasmonic devices. We aim to examine plasmonic modes in such periodic systems by calculating complex optical frequency as a function of in-plane wavenumber of the mode, as well as the Bragg scattering of light caused by these modes.
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