Abstract
In this work, we investigate the propagation of designer surface plasmons in planar perfect electric conductor structures that are subject to a parabolic graded-index distribution. A three-dimensional, fully vectorial finite-difference time-domain method was used to engineer a structure with a parabolic effective group index by modulating the dielectric constant of the structure's square holes. Using this structure in our simulations, the lateral confinement of propagating designer surface plasmons is demonstrated. Focusing, collimation and waveguiding of designer plasmons in the lateral direction is realized by changing the width of the source beam. Our findings contribute to applications of designer surface plasmons that require energy concentration, diffusion, guiding, and beam aperture modification within planar perfect electric conductors. .
Highlights
Extraordinary optical transmission (EOT) is the enhanced transmission of incident electromagnetic radiation through sub-wavelength-scale holes in metallic films. [1, 2] EOT in real metals is based on two types of surface waves: 1) conventional surface plasmons (SPs) that are excited at a metal-dielectric interface, and 2) surface-bound states that exist on structured perfect electric conductor (PEC) surfaces
The use of Gaussian beams is appropriate in the context of THz plasmonics, since surface modes are excited on planar structures using Gaussian beams incident upon razor-blade-like structures. [37]
Using finite-difference time-domain (FDTD) simulations we have demonstrated that one can control the propagation of DSPs in structured PEC materials with arrays of square holes by exploiting graded index media
Summary
Extraordinary optical transmission (EOT) is the enhanced transmission of incident electromagnetic radiation through sub-wavelength-scale holes in metallic films. [1, 2] EOT in real metals is based on two types of surface waves: 1) conventional surface plasmons (SPs) that are excited at a metal-dielectric interface, and 2) surface-bound states that exist on structured perfect electric conductor (PEC) surfaces. Structured PEC surfaces and the excited DSPs have recently garnered interest within the photonics community, as a new platform to engineer surface-bound states of a wide frequency range. [11, 12, 13, 14] An important example is the guiding of terahertz-range radiation [15, 16] in the form of DSPs. Structured PEC surfaces and the excited DSPs have recently garnered interest within the photonics community, as a new platform to engineer surface-bound states of a wide frequency range. By placing two optimized metallic grating structures on opposite sides of a narrow slit, Gan et al were able to selectively guide terahertz-range waves along the two desired directions. [21] metallic gratings have been found to significantly decrease the group velocity near the cutoff frequency. [22] Gan et al [23] extended this notion by using graded metallic gratings to slow the propagation of widebandwidth, terahertz-range DSPs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
