Modified Brewster angle on conducting 2D materials

Abstract

Insertion of 2D materials in optical systems modifies their electrodynamical response. In particular, the Brewster angle undergoes an up-shift if a substrate is covered with a conducting 2D material. This work theoretically and experimentally investigates this effect related to the 2D induced current at the interface. The shift is predicted for all conducting 2D materials and tunability with respect to the Fermi level of graphene is evidenced. Analytical approximations for high and low 2D conductivities are proposed and avoid cumbersome numerical analysis of experimental data. Experimental demonstration using spectroscopic ellipsometry has been performed in UV to NIR range on mono-, bi-and trilayer graphene samples. The non-contact measurement of this modified Brewster angle allows to deduce the optical conductivity of 2D materials. Applications to telecommunication technologies can be considered thanks to the tunability of the shift at 1.55 µm.

Experimental Study of Few‐Layer Graphene: Optical Anisotropy and Pseudo‐Brewster Angle Shift in Vacuum Ultraviolet Spectral Range

“…On the contrary, the effect of graphene layer on top of SiO 2 is the shift of the pseudo‐Brewster angle to larger values in the visible range. [ 43,44 ]…”

Unveiling optical in-plane anisotropy of 2D materials from oblique incidence of light

“…This expression also reproduces a previous result found by Majérus et.al. [10] in certain limiting case. Moreover, it is demonstrated that for σ xy = 0 the perfect suppression of the p-polarization reflectance is inhibited and, thus, the Brewster effect does not occur strictly.…”

Enhancing light‐matter interaction in 2D materials by optical micro/nano architectures for high‐performance optoelectronic devices

“…[149][150][151] Majérus et al experimentally realized a Brewster angle shift in the ultraviolet-visible to near-infrared range by covering mono-, bi-, and trilayer graphene on the substrate, as shown in Figure 15B. 152 Chen et al showed an electrically tunable Brewster device in THz for the first time, in which the Brewster angle could be electrically tuned from 65 to 72 ( Figure 15C and D). 150 The Brewster device was operated as both an intensity and phase modulator.…”

“…The tunable Brewster angle effect based on graphene has been demonstrated in different wavelength regions and also used in different optical devices 149‐151 . Majérus et al experimentally realized a Brewster angle shift in the ultraviolet‐visible to near‐infrared range by covering mono‐, bi‐, and trilayer graphene on the substrate, as shown in Figure 15B 152 . Chen et al showed an electrically tunable Brewster device in THz for the first time, in which the Brewster angle could be electrically tuned from 65° to 72° (Figure 15C and D).…”

“…B, Brewster angle for a glass substrate, and mono‐, bi‐, and trilayer graphene. Reproduced with permission 152 . Copyright 2018, Institute of Physics.…”