Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Two-beam coupling by a hot electron nonlinearity



Jagannath Paul, Mario Miscuglio, Yaliang Gui, Volker Sorger, Jared Wahlstrand


Transparent conductive oxides such as indium tin oxide (ITO) have attracted much recent interest for their enhanced optical nonlinearity near the epsilon near zero wavelength. The nonlinearity of these materials is caused by laser heating of electrons, with a subpicosecond relaxation time due to cooling to the lattice. We consider two beam interaction in a material with a hot electron nonlinearity. A nonlinear transient grating modifies the effective nonlinearity experienced by one pulse from the other. Theoretical results are compared to polarization- and chirp-dependent pump- probe experiments on an ITO film. Two-beam coupling can enhance and modify the nonlinearity in a slightly nondegenerate pump-probe scheme, which could impact applications such as all-optical modulation. Our results apply to the interpretation of pump-probe experiments on any material with a hot electron nonlinearity.
Optics Letters


nonlinear optics, pump-probe, ultrafast optics


Paul, J. , Miscuglio, M. , Gui, Y. , Sorger, V. and Wahlstrand, J. (2021), Two-beam coupling by a hot electron nonlinearity, Optics Letters, [online],, (Accessed April 20, 2024)
Created January 14, 2021, Updated October 12, 2021