Anisotropic optical properties of monolayer aligned single‐walled carbon nanotubes

Abstract

Two‐dimensional materials are the fundamental building blocks for modern optoelectronics and photonics. Optically anisotropic monolayers give even more flexibility in device design and performance. However, the random orientation of optical axes in the large‐scale samples prevents anisotropic monolayers from widespread use. The alternative structure is a monolayer of aligned single‐walled carbon nanotubes (SWCNTs) with an anisotropic dielectric tensor. Here, we measure aligned SWCNTs monolayer anisotropic optical constants in a broad spectral range (250 – 1700 nm) for the first time. We discovered that it has a large birefringence of Δn ∽ 0.2 and a high dichroism of Δk ∽ 0.4. Moreover, we demonstrated that aligned SWCNTs monolayer optical response could be described by an effective medium approximation using the graphene dielectric function. Besides, it gives a universal approach for a determination of carbon concentration in nanotubes structures. It also applies for other types of carbon nanotubes, such as multi‐walled and randomly oriented carbon nanotubes arrays. Hence, our results add aligned SWCNTs monolayer optical constants to the optical anisotropy database, which facilitates the longstanding challenge of using one‐dimensional structures in two dimensions, and provide a rapid characterization method for carbon nanotubes.This article is protected by copyright. All rights reserved.