Universal charts for optical difference frequency generation in the terahertz domain

TL;DR

This paper introduces a universal, normalized chart-based method for predicting optical-to-terahertz conversion efficiency in difference frequency generation, simplifying analysis across various systems and materials.

Contribution

It presents a new universal approach using normalized charts that accurately predicts efficiency and estimates nonlinear coefficients in terahertz generation systems.

Findings

Predictions align well with experimental results

Method enables estimation of nonlinear coefficients

Simplifies analysis of difference frequency generation

Abstract

We present a universal and rigorous approach to study difference frequency generation in the terahertz domain, keeping the number of degrees of freedom to a minimum, through the definition of a suitable figure of merit. The proposed method relies on suitably normalized charts, that enable to predict the optical-to-terahertz conversion efficiency of any system based on wave propagation in quadratic nonlinear materials. The predictions of our approach are found to be in good agreement with the best experimental results reported to date, enabling also to estimate the d22 nonlinear coefficient of high quality GaSe.