July 2018
Spotlight Summary by Johann Toudert
Theory of plasmon reflection by a 1D junction
The demonstration of terahertz plasmons with long propagation distance in graphene has opened a path to developing two-dimensional photonic circuits analogous to the electronic ones, yet driven at higher frequencies. To embed switching functionalities into such circuits, the incorporation of a narrow low-conductivity junction has been proposed. By tuning the conductivity of this junction, it can reflect or transmit an incident plasmon wave. However, it was not well understood why a plasmon could be reflected by such a deeply subwavelength structure. In this context, Bor-Yuan Jiang and coworkers provide analytical solutions for the plasmon reflectance of a junction incorporated in a two-dimensional conducting slab, together with an equivalent circuit model. Reflectance is calculated as a function of the junction width and conductivity, and several regimes are evidenced. For a very small width (a few percent of the plasmon wavelength), the junction does not behave anymore as a standard Fabry-Pérot cavity. In contrast, its response is dictated by capacitive coupling between the two edges. In this regime, a resonance with near-total reflectance occurs if the junction conductivity is tuned to a suitable value. By detuning the conductivity from that particular value, reflectance decreases and the junction transmits the plasmon wave.
You must log in to add comments.
Add Comment
You must log in to add comments.
Article Information
Theory of plasmon reflection by a 1D junction
Bor-Yuan Jiang, Eugene J. Mele, and Michael M. Fogler
Opt. Express 26(13) 17209-17226 (2018) View: Abstract | HTML | PDF