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The unique terahertz properties of graphene has been identified for novel optoelectronic applications. In a graphene sample with bias voltage added, there is an enhanced absorption in the far infrared region and a diminished absorption in…

Mesoscale and Nanoscale Physics · Physics 2017-05-18 Yuan Yang , Grigory Kolesov , Lucas Kocia , Eric J. Heller

Monolayer graphene absorbs 2.3 percent of the incident visible light. This 'small' absorption has been used to emphasize the visual transparency of graphene, but it in fact means that multilayer graphene absorbs a sizable fraction of…

The ultrafast response and broadband absorption of all-optical graphene switches are highly desirable features for on-chip photonic switching. However, because graphene is an atomically thin material, its absorption of guided optical modes…

We present a degenerate four-wave mixing experiment on a silicon nitride (SiN) waveguide covered with gated graphene. We observe strong dependencies on signal-pump detuning and Fermi energy, i.e. the optical nonlinearity is demonstrated to…

It is shown that one can explore the optical conductivity of graphene, together with the ability of controlling its electronic density by an applied gate voltage, in order to achieve resonant coupling between an external electromagnetic…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 Yu. V. Bludov , M. I. Vasilevskiy , N. M. R. Peres

The optical conductance of monolayer graphene is defined solely by the fine structure constant. The absorbance has been predicted to be independent of frequency. In principle, the interband optical absorption in zero-gap graphene could be…

Molecular adsorption is pivotal in device fabrication and material synthesis for quantum technology. However, elucidating the behavior of physisorption poses technical challenges. Here graphene with ultrahigh sensitivity was utilized to…

Electronic devices using epitaxial graphene on Silicon Carbide require encapsulation to avoid uncontrolled doping by impurities deposited in ambient conditions. Additionally, interaction of the graphene monolayer with the substrate causes…

On the basis of the Kubo formula we evaluated the optical conductivity of a graphene sheet. The full behavior of frequency as well as temperature dependence of the optical conductivity is presented. We show that the anisotropy of…

Mesoscale and Nanoscale Physics · Physics 2008-10-07 Chao Zhang , Lei Chen , Zhongshui Ma

Terahertz (THz) anisotropic absorption in graphene could be significantly modified upon applying a static magnetic field on its ultra-fast 2D Dirac electrons. In general, by deriving the generalized Fresnel coefficients for monolayer…

Mesoscale and Nanoscale Physics · Physics 2023-05-03 D. Jahani , O. Akhavan , A. Alidoust Ghatar

Graphene and related two-dimensional materials are promising candidates for atomically thin, flexible, and transparent optoelectronics. In particular, the strong light-matter interaction in graphene has allowed for the development of…

Graphene is a unique platform for tunable opto-electronic applications thanks to its linear band dispersion, which allows electrical control of resonant light-matter interactions. Tuning the nonlinear optical response of graphene is…

We report a versatile and cost-effective way of controlling the unsaturated loss, modulation depth and saturation fluence of graphene-based saturable absorbers (GSAs), by changing the thickness of a spacer between SLG and a high-reflection…

The enhanced nonlinear optical response of a one-dimensional (1D) photonic crystal (PC) made from polymers and graphene composites is observed. The graphene PC was fabricated by spin-coating. It shows obvious bandgaps at two wavelengths in…

In this letter, we report a method to control reflection phase of microwaves using electrically tunable graphene devices. The device consists of mutually gated large-area graphene layers placed at a quarter-wave distance from a metallic…

Applied Physics · Physics 2018-01-17 Osman Balci , Nurbek Kakenov , Coskun Kocabas

Graphene based THz modulators are promising due to the conical band structure and high carrier mobility of graphene. Here, we tune the Fermi level of graphene via electrical gating with the help of ionic liquid to control the THz…

Dynamic wavelength tunability has long been the holy grail of photodetector technology. Because of its atomic thickness and unique properties, graphene opens up new paradigms to realize this concept, but so far this has been elusive…

Mesoscale and Nanoscale Physics · Physics 2017-03-08 François Léonard , Catalin D. Spataru , Michael Goldflam , David W. Peters , Thomas E. Beechem

We demonstrate tunable Schottky barrier height and record photo-responsivity in a new-concept device made of a single-layer CVD graphene transferred onto a matrix of nanotips patterned on n-type Si wafer. The original layout, where…

In this paper, we exploit the metagrating paradigm to achieve coherent control of absorption and reflection in a two-port device. Employing graphene ribbon as a tunable element allows us to, for the first time, realize a reconfigurable…

Optics · Physics 2020-11-11 Ensiye Ghorbanpour , Sahar Behroozinia , Ali Abdolali

Among its many outstanding properties, graphene supports terahertz surface plasma waves -- sub-wavelength charge density oscillations connected with electromagnetic fields that are tightly localized near the surface[1,2]. When these waves…