Enhancing the ultrafast third order nonlinear optical response by charge transfer in VSe2-reduced graphene oxide hybrid

TL;DR

This paper demonstrates that a VSe2-reduced graphene oxide hybrid significantly enhances ultrafast third-order nonlinear optical responses through charge transfer, with potential applications in optical limiting and photonics.

Contribution

The study introduces a charge donor-acceptor hybrid material that markedly improves third-order nonlinearities, supported by theoretical and experimental analysis.

Findings

Enhanced third-order nonlinearities by at least one order of magnitude

Strong electronic coupling confirmed by photoluminescence measurements

Ultrafast optical limiter device with improved threshold and transmittance

Abstract

Nonlinear optical phenomena play a critical role in understanding microscopic light-matter interactions and have far-reaching applications across various fields, such as biosensing, quantum information, optical switching, and all-optical data processing. Most of these applications require materials with high third-order absorptive and refractive optical nonlinearities. However, most materials show weak nonlinear optical responses due to their perturbative nature and often need to be improved for practical applications. Here, we demonstrate that the charge donor-acceptor hybrid of VSe2-reduced graphene oxide (rGO) hybrid exhibits enhanced ultrafast third-order absorptive and refractive nonlinearities compared to the pristine systems, at least by one order of magnitude. Through density functional theory and Bader charge analysis, we elucidate the strong electronic coupling in the VSe2-rGO hybrid, involving the transfer of electrons from VSe2 to rGO. Steady-state and time-resolved photoluminescence (PL) measurements confirm the electronic coupling and charge transfer. Furthermore, we fabricate an ultrafast optical limiter device with better performance parameters, such as an onset threshold of 2.5 mJ cm-2 and differential transmittance of 0.42.