Terahertz generation via all-optical quantum control in 2D and 3D materials

TL;DR

This study demonstrates a universal optical method for generating and analyzing terahertz radiation in 2D and 3D materials, enabling material comparison and potential new applications without electrodes.

Contribution

It introduces a novel all-optical approach to generate and detect terahertz radiation in diverse materials, bypassing traditional electrode-based methods.

Findings

THz emission amplitude scales similarly in graphene and GaAs

Current direction mapping is consistent across materials

Method enables direct measurement of electron scattering timescales

Abstract

Using optical technology for current injection and electromagnetic emission simplifies the comparison between materials. Here, we inject current into monolayer graphene and bulk gallium arsenide (GaAs) using two-color quantum interference and detect the emitted electric field by electro-optic sampling. We find the amplitude of emitted terahertz (THz) radiation scales in the same way for both materials even though they differ in dimension, band gap, atomic composition, symmetry and lattice structure. In addition, we observe the same mapping of the current direction to the light characteristics. With no electrodes for injection or detection, our approach will allow electron scattering timescales to be directly measured. We envisage that it will enable exploration of new materials suitable for generating terahertz magnetic fields.