A closed-form approximate expression for the optical conductivity of graphene

Abstract

A closed-form approximate expression for the optical conductivity of graphene is developed, which generates results with less than 0.8% maximum absolute error for λ>250 nm. The expression takes wavelength, temperature, chemical potential, and hopping parameter into account and provides a fast, easy, and reliable alternative to well-known methods that include singular integrals. Numerical results confirm that the effective complex electrical permittivity derived from the optical conductivity successfully represents this one atom thick material in three-dimensional electromagnetic simulations and analyses.

Characterization of tunable graphene metasurfaces over an ultrawide terahertz band using a 1‐step leapfrog hybrid implicit‐explicit FDTD method

“…Assume that the monolayer graphene surface is located in the x ‐ y plane with 1 biasing electrostatic field in the z axis. Then, its surface conductivity, written as σ s = σ r + jσ i , can be described by…”

“…To model the dispersive feature of graphene conductivity, the auxiliary differential equation (ADE) method with high accuracy and efficiency during its simulation of complex media is implemented into the leapfrog HIE‐FDTD algorithm. During the implementation of ADE, the conductivity function of graphene is described by a new closed‐form approximate expression, which is suitable for terahertz as well as infrared bands, instead of the normally used Drude model for the frequency up to 10 THz. As the conductivity expression is a complex function, it must be turned into the sum of multiple complex‐conjugate pole‐residue pairs using the vector‐fitting technique for further FDTD coding …”

Novel graphene-based photonic devices for efficient light control and manipulation

“…Both interband and intraband effects have been taken into account to evaluate the relation between the graphene conductivity and the chemical potential μ c [13] in the near-infrared range. The relative permittivity of graphene is given by ε = 1 + iσ/ωε 0 Δ, where σ is the complex conductivity, ω is the angular frequency, ε 0 the vacuum permittivity, i is the imaginary unit, and Δ the graphene thickness.…”

Determining optical constants of 2D materials with neural networks from multi-angle reflectometry data

“…Depending on their family, these 2D materials exhibit unique properties such as high electrical conductivity, thermal stability, and mechanical strength [13,15,18]. With more sophisticated synthesis methods, such as chemical vapor deposition (CVD) that can generate large area and high-quality samples, they become attractive materials with a promising potential to be used in future optical, opto-electronic, and quantum devices.…”