Ultrafast Optical Nonlinearity in PMMA-TiO2 Nanocomposites

TL;DR

This paper reports on the ultrafast optical nonlinearity observed in PMMA-TiO2 nanocomposite films using femtosecond laser pulses, highlighting their potential for all-optical switching applications.

Contribution

It demonstrates the synthesis of PMMA-TiO2 nanocomposites with significant nonlinear optical properties and characterizes their ultrafast response for the first time.

Findings

Optimal nonlinearity in 60% TiO2 films

Presence of 5-nm TiO2 particles confirmed by TEM

Nonlinear response recovery time of ~1.5 ps

Abstract

With 780-nm, 250-fs laser pulses, ultrafast optical nonlinearity has been observed in a series of thin films containing PMMA-TiO2 nanocomposites, which are synthesized by a simple technique of in-situ sol-gel/polymerization. The best figures of merit are found in one of the films prepared with a 60% weight percentage of titanium isopropoxide. TEM shows the presence of the 5-nm-diameter particles in the film. The observed optical nonlinearity has a recovery time of ~1.5 ps. These findings suggest the strong potential of PMMA-TiO2 nanocomposites for all-optical switching.