# Universal long-wavelength nonlinear optical response of noble gases

## TL;DR

This paper reveals a universal scaling law for the long-wavelength nonlinear optical response of noble gases, enabling better understanding and characterization of their behavior in mid-infrared applications.

## Contribution

The study introduces a universal scaling framework for noble gases' nonlinear response, combining metastable state analysis and scaling techniques.

## Key findings

- Universal functions describe noble gases' nonlinear dipole moments and ionization rates.
- Scaling laws unify responses across different noble gases.
- Provides new tools for mid-infrared optical filamentation research.

## Abstract

We demonstrate numerically that the long-wavelength nonlinear dipole moment and ionization rate versus electric field strength $F$ for different noble gases can be scaled onto each other, revealing universal functions that characterize the form of the nonlinear response. We elucidate the physical origin of the universality by using a metastable state analysis of the light-atom interaction in combination with a scaling analysis. Our results also provide a powerful new means of characterizing the nonlinear response in the mid-infrared and long-wave infrared for optical filamentation studies.