FLEET Seminar: Yunyi Yang – 3D graphene metamaterial platform for on-chip photonic device

3D graphene metamaterial platform for on-chip photonic device

Dr Yunyi Yang

Centre for Micro-Photonics, Swinburne University of Technology, Melbourne, Australia

All welcome! The seminar flyer can be downloaded here

Abstract:

Two-dimensional (2D) materials, especially for graphene-based materials, have attracted significant research interests due to their unique optical and electrical properties. These properties are only remained in 2D scale, which would not exist in their bulk morphologies. The ultrathin nature (3.4 Å) and low optical absorption of monolayer graphene over a broadband wavelength restrict its ability to provide sufficient optical modulation, which limits performance in photonic applications.

Graphene-based metamaterials (GM), with alternating graphene and dielectric layers, are artificially structured materials designed to attain an extremely high optical response that can enhance optical modulation. Recent researches have suggested that these materials can be useful in the photonics area, including light-harvesting, light-emitting devices, all-optical communication devices.

In this talk, I will present a low cost, solution-phase method that is able to build multilayered metamaterials by using 2D materials as the building blocks. The prepared GM can firmly attach to the substrate with uniform distribution. The phototunable GM architectures are enabled by laser fabrication, which can lead to reconfigurable applications.

Dynamic tuning of the optical properties (n & k) and the bandgap of the GM has been realized through laser-induced reduction. The amplitude and phase modulation devices, which are a quick response (QR) code and an ultrathin flat lens, have been fabricated on this platform. By further exploiting the surface properties, the GM can be conformally coated onto the Si nanostructures.

A significant improvement in both the optical and electrical properties of the hybrid devices has been observed from GM conformal coated Si solar cells. The efficiency of the hybrid devices is increased by ~25% after the GM coating. By incorporating GM with integrated photonic devices, enhanced four-wave mixing in the hybrid waveguide has been obtained. Moreover, due to the high anisotropy of GM, hybrid GM waveguide and micro-ring resonator polarizers have been achieved with high extinction ratio. The layer assembled GM platform provides an effective approach to achieving an accurately controlled and cost-effective graphene coating.

About the Speaker: 

Dr Yunyi Yang is a postdoctoral researcher at Centre for Micro-Photonics, Swinburne University of Technology, where he completed his PhD in applied physics in 2019. Dr. Yunyi Yang’s research focuses on frontier technologies between advanced 2D materials and nanophotonic devices, including 2D metamaterial synthesis, functional structure design, laser/nano fabrication, laser-material interaction and integrated photonics.

From 2019, he is focusing on the study of the nonlinear behaviour in 2D material incorporated integrated photonic devices, including waveguide, micro-ring resonator based on Si, SiN and doped silica platform.