All-optical control in metal nanocomposites due to a reversible transition between the local-field-enhancement and a local-field-depression upon irradiation by ultrashort control-pulses of light

TL;DR

This paper theoretically investigates how ultrashort light pulses can reversibly switch metal nanocomposites between dielectric and metallic states by modulating local-field effects, enabling ultrafast optical control.

Contribution

It introduces a theoretical model demonstrating reversible optical switching in metal nanocomposites via local-field modulation induced by ultrashort pulses.

Findings

Reversible transition between local-field-enhancement and depression.

Nanocomposites behave as dielectric or metal depending on control pulse.

Potential for ultrafast, remote optical control applications.

Abstract

We theoretically study on non-perturbative effective nonlinear responses of metal nanocomposites based on the intrinsic third-order nonlinear response of metal nanoparticles. The large intrinsic third-order nonlinear susceptibility of metal nanoparticles and an irradiation by ultrashort control pulse of light with a sufficiently high peak intensity and moderate fluence can induce a local-field-depression and a saturated plasmon-bleaching in metal nanoparticles. If the control pulse is on, the metal nanocomposites can behave like a dielectric due to the local-field-depression, while if the control pulse is off, the metal nanocomposites can behave like a metal showing a high absorption due to the local-field-enhancement at the plasmon-resonance. This phenomenon can be applied to an ultrafast and remote control of light in metal nanocomposites.