Broadband optical parametric amplification by two-dimensional semiconductors

TL;DR

This paper demonstrates ultrathin, single-pass optical parametric amplification using 2D semiconductors, enabling broadband, polarization-independent amplification at atomic thicknesses, with potential applications in nanophotonics and quantum technologies.

Contribution

It introduces a novel approach to achieve nonlinear optical amplification at the atomic layer limit using 2D semiconductors, bypassing phase-matching constraints.

Findings

Amplification achieved over a single atomic layer of 2D material.

Amplification bandwidths are ultrabroad and polarization-independent.

First-principle calculations confirm polarization invariance and power relationships.

Abstract

Optical parametric amplification is a second-order nonlinear process whereby an optical signal is amplified by a pump via the generation of an idler field. It is the key ingredient of tunable sources of radiation that play an important role in several photonic applications. This mechanism is inherently related to spontaneous parametric down-conversion that currently constitutes the building block for entangled photon pair generation, which has been exploited in modern quantum technologies ranging from computing to communications and cryptography. Here we demonstrate single-pass optical parametric amplification at the ultimate thickness limit; using semiconducting transition-metal dichalcogenides, we show that amplification can be attained over a propagation through a single atomic layer. Such a second-order nonlinear interaction at the 2D limit bypasses phase-matching requirements and achieves ultrabroad amplification bandwidths. The amplification process is independent on the in-plane polarization of the impinging signal and pump fields. First-principle calculations confirm the observed polarization invariance and linear relationship between idler and pump powers. Our results pave the way for the development of atom-sized tunable sources of radiation with applications in nanophotonics and quantum information technology.