Largely Tunable Terahertz Circular Polarization Splitters Based on Patterned Graphene Nanoantenna Arrays

Abstract

Dynamic manipulation of wavefront is vital for massive free-space optical applications. Here we propose a set of largely tunable circular polarization splitters leveraging graphene nanoantennas with high efficiency reaching 83% and wide frequency tunability range of 2 to 5 THz. By synergizing the electrically tunable surface plasmons of graphene with phase gradient metasurface, we numerically demonstrate two kinds of polarization splitters with complimentary graphene patterns to realize electrical tuning of operation frequency and efficient circular polarization demultiplexing. Using antennas of different geometric sizes, the device performances are investigated in several different terahertz bands. Our proposed structures can facilitate dynamically tunable broadband and high-speed applications such as polarization demultiplexing and optical switches in terahertz regime.

Freestanding Membranes for Unique Functionality in Electronics

“…For example, it was recently reported that 2D materials help strain relaxation during heteroepitaxial growth because of their slippery nature . Moreover, electronic and optical thin films can be combined with various 2D materials to realize numerous hybrid metadevices to further expand functionality to enhance device performance. − Furthermore, cost reduction of material production by substrate recycling will give a chance to utilize expensive materials in the commercial market. Thus, the success of further development in the layer transfer technology will bring a new world in the electronic era with new physics, new device architectures, and new electronic applications.…”

Optical meta-waveguides for integrated photonics and beyond

“…For instance, plasmon polaritons in graphene/ hexagonal boron-nitride (h-BN) heterostructures exhibited a long intrinsic propagation length exceeding 10 µm (about 50 plasmonic wavelengths) 515 . Graphene can also be patterned with subwavelength structures to facilitate various metawaveguide devices for beam steering 516,517 , non-reciprocal SPP propagation 518 and topological edge plasmon 519 . In addition, plasmonic meta-waveguides carrying strongly enhanced local fields offer us a good platform for tunable light-matter interactions (e.g., nonlinear and Raman effects) when integrated with two-dimensional materials such as MoS 2 and graphene 348,520 .…”

Functionalizing nanophotonic structures with 2D van der Waals materials

“…The metasurface structure can also enable enhanced light-2D material applications for spontaneous control over harmonic signal generation and beam control. 137,304 At the same time, the 2D materials can be also patterned into atomically thin metasurfaces for tunable planar optics, 305,306 light sources, 307,308 beam splitters, 309 and so on.…”