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Enhanced optical absorption in two-dimensional (2D) materials has recently moved into the focus of nanophotonics research. In this work, we present a gain-assisted method to achieve critical coupling and demonstrate the maximum absorption…

Optics · Physics 2021-03-02 Tingting Liu , Chaobiao Zhou , Shuyuan Xiao

We investigate the effect of hydrogen coverage on the optical conductivity of single-side hydrogenated graphene from first principles calculations. To account for different degrees of uniform hydrogen coverage we calculate the complex…

Materials Science · Physics 2015-06-17 Sebastian Putz , Martin Gmitra , Jaroslav Fabian

We study plasmonic resonances in electrostatically gated graphene nanoribbons on silicon dioxide substrates. Absorption spectra are measured in the mid-far infrared and reveal multiple peaks, with width-dependent resonant frequencies. We…

Mesoscale and Nanoscale Physics · Physics 2014-12-02 Isaac. J. Luxmoore , Choon How Gan , Peter Q. Liu , Federico Valmorra , Penglei Li , Jerome Faist , Geoffrey R. Nash

We present calculations of the optical absorption and electro-absorption spectra of graphene nanoribbons (GNRs) using a $\pi-$electron approach, incorporating long-range Coulomb interactions within the Pariser-Parr-Pople (PPP) model…

Materials Science · Physics 2011-02-14 Kondayya Gundra , Alok Shukla

Undoped graphene is semi-metallic and thus not suitable for many electronic and optoelectronic applications requiring gapped semiconductor materials. However, a periodic array of holes (antidot lattice) renders graphene semiconducting with…

Mesoscale and Nanoscale Physics · Physics 2008-06-24 Thomas G. Pedersen , Christian Flindt , Jesper Pedersen , Antti-Pekka Jauho , Niels Asger Mortensen , Kjeld Pedersen

Topological insulator films are promising materials for optoelectronics due to a strong optical absorption and a thickness dependent band gap of the topological surface states. They are superior candidates for photodetector applications in…

Mesoscale and Nanoscale Physics · Physics 2018-09-11 Mathias Rosdahl Brems , Jens Paaske , Anders Mathias Lunde , Morten Willatzen

We study the influence of different kinds of gaps in a quasiparticle spectrum on longitudinal and transverse optical conductivities of bilayer graphene. An exact analytical expression for magneto-optical conductivity is derived using a…

Strongly Correlated Electrons · Physics 2012-08-08 E. V. Gorbar , V. P. Gusynin , A. B. Kuzmenko , S. G. Sharapov

Hydrogen adsorption on graphene in commensurate periodic arrangements leads to bandgap opening at the Dirac point and the emergence of dispersionless midgap bands. We study these bandgap effects and their dependence on periodicity for a…

Mesoscale and Nanoscale Physics · Physics 2012-05-15 Mahboobeh Mirzadeh , Mani Farjam

We theoretically predict and experimentally demonstrate inhibition of linear absorption for phase and group velocity mismatched second and third harmonic generation in strongly absorbing materials, GaAs in particular, at frequencies above…

We present a framework to calculate the anisotropic and non-linear photoconductivity for two band systems with application to graphene. In contrast to the usual perturbative (second order in the optical field strength) techniques, we…

Mesoscale and Nanoscale Physics · Physics 2018-01-10 Ashutosh Singh , Saikat Ghosh , Amit Agarwal

Motivated by the idea of smart metasurfaces, we will demonstrate a graphene-based tunable absorber in which perfect absorption can be achieved for all angles of incidence, only by tuning the Fermi level of graphene. We place an unpatterned…

Applied Physics · Physics 2018-03-23 Xu-Chen Wang , Sergei A. Tretyakov

In this work, we investigated a simple structured graphene terahertz (THz) metasurface (MSF) with perfect absorption, wideband, polarization insensitive, oblique incidence insensitive and frequency reconfiguration. The graphene MSF…

Signal Processing · Electrical Eng. & Systems 2019-10-21 Sasmita Dash , Christos Liaskos , Ian F. Akyildiz , Andreas Pitsillides

Direct access to the electric field of light provides a subcycle view of the polarization response of matter, thus enabling sensitive metrology in physics, chemistry, and medicine. Optical-field sampling techniques take advantage of some…

Optics · Physics 2021-11-19 Dmitry A. Zimin , Vladislav S. Yakovlev , Nicholas Karpowicz

The ability to manipulate electrons with the intense laser pulse enables an unprecedented control over the electronic motion on its intrinsic timescale. Present work explores the desired control of photocurrent generation in monolayer…

Mesoscale and Nanoscale Physics · Physics 2024-08-14 Navdeep Rana , Gopal Dixit

We develop a microscopic theory of a strong electromagnetic field interaction with gated bilayer graphene. Quantum kinetic equations for density matrix are obtained using a tight binding approach within second quantized Hamiltonian in an…

Mesoscale and Nanoscale Physics · Physics 2017-05-24 A. A. Avetisyan , A. P. Djotyan , K. Moulopoulos

We propose a theory of optical absorption in monolayer graphene-hexagonal boron nitride (hBN) heterostructures. In highly oriented heterostructures, the hBN underlay produces a long-range moir\'e superlattice potential for the graphene…

Mesoscale and Nanoscale Physics · Physics 2013-12-10 D. S. L. Abergel , J. R. Wallbank , Xi Chen , M. Mucha-Kruczyński , Vladimir I. Fal'ko

Graphene is known to possess strong optical nonlinearity. Its nonlinear response can be further enhanced by graphene plasmons. Here, we report a novel nonlinear electro-absorption effect observed in nanostructured graphene due to excitation…

Mesoscale and Nanoscale Physics · Physics 2018-02-14 D. Kundys , B. Van Duppen , O. P. Marshall , F. Rodriguez , I. Torre , A. Tomadin , M. Polini , A. N. Grigorenko

We discuss synchrotron absorption of a short electromagnetic pulse that propagates in a cold magnetized pair plasma. We show that the pulse can be absorbed when $\omega_{\rm B}/a_0< \omega< a_0\omega_{\rm B}$, where $a_0>1$ is the strength…

High Energy Astrophysical Phenomena · Physics 2025-12-08 Emanuele Sobacchi

Metallic layers are known to be used for the suppression of wave transmission when their thickness is sufficiently higher than the skin depth of metal. If in addition to blocking the transmission, metallic layers have the feature of…

We theoretically investigate the interaction of an ultrastrong femtosecond-long linearly polarized optical pulse with AB-stacked bilayer graphene. The pulse excite electrons from the valence into the conduction band, resulting in finite…

Mesoscale and Nanoscale Physics · Physics 2021-08-11 Pardeep Kumar , Thakshila M. Herath , Vadym Apalkov , Mark I. Stockman