Loading...

Design and Simulation of Computational Operators with Graphene Metastructures

Abdollah Ramezani, Sajjad | 2015

598 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47986 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Khavasi, Amin; Kavehvash, Zahra
  7. Abstract:
  8. In this dissertation, some computational operators are designed and simulated using plasmonic metastructures. Superiority of graphene over its plasmonics counterparts in terms of exceptional features such as tunability, thinness, and also highly confined graphene plasmons intrigued us to employ graphene-based meta-transmit-array for designing efficient devices in the infrared regime. First off, we propose a transmit-array of metasurfaces containing subwavelength graphene ribbons and evaluate the structure capability in full controlling over amplitude and phase of the impinging wave locally. By considering optics nanocircuits concept, an equivalent admittance is assigned to each metasurface and then a transmission line model will be suggested to investigate the behavior of the whole structure. According to geometrical optics, we implement two functionalities, i.e. lens and beam splitter, and show their unprecedented efficiency through full-wave simulations. Moreover, to evaluate the performance of the configuration in modulating the electromagnetic phase and amplitude responses, a differentiator is realized. Finally, to be experimentally feasible, a new configuration will be proposed which can concentrate light at various focal planes and angles by employing an external variable gate voltage. Apart from that, the new concept of “metalines” is introduced in which by employing the analytical results of graphene surface plasmons scattering from an one dimensional discontinuity in graphene surface conductivity, their capability in molding amplitude and phase of graphene-plasmons wave is investigated. Employing the general concepts of spatial Fourier transformation, we implement computational operators by assigning an appropriate transfer function to the meta-transmit-array embedded between two graded index lenses. Not only is the proposed structure more compact than the recent works, but also the output results are in more agreement with the analytical ones. In summary, the proposed metasurfaces and metalines enable us to implement the nanophotonics and optoelectronics applications on miniaturized and integrable platforms
  9. Keywords:
  10. Graphine ; Transmission-line Model ; PLasmonic Structure ; Transmit Array ; Metasurfaces ; Metalines ; Computational Operators

 Digital Object List

 Bookmark

No TOC