Plasmonic nanoparticles offer a broad range of functionalities, owing to their ability to amplify light in the near-field or convert it into heat. However, their ultrafast nonlinear optical response remains too low to envisage all-optical high-rate photonic processing applications. Here, we tackle this challenge by coupling the localized plasmon mode in gold nanoparticles with a localized photonic mode in a 1D resonant cavity. Despite the nonradiative losses, we demonstrate that a strong, reversible, and ultrafast optical modulation can be achieved. By using a light pumping fluence of less than 1 mJ cm(-2), a change of signal transmittance of more than 100% is generated within a few picosecond time scale. The nanoparticle transient optical response is enhanced by a factor of 30 to 40 while its spectral profile is strongly sharpened. The large nonlinear response of such plasmonic cavities could open new opportunities for ultrafast light processing at the nanoscale.

Abstract:In this work we present, for the first time to our knowledge, laser emission under wavelength selective laser-pulsed pumping in Nd 3+ -doped TeO 2 -ZnO-ZnF 2 bulk glass for two different Nd 3+ concentrations. The fluorescence properties of Nd 3+ ions in this matrix which include, JuddOfelt calculation, stimulated emission cross-section of the laser transition and lifetimes are also presented. The site-selective emission and excitation spectra along the 4 I 9/2 → 4 F 3/2 absorption band show the inhomogeneous behaviour of the crystal field felt by Nd 3+ ions in this fluorotellurite glass which allows for spectral tuning of the laser output pulse as a function of the pumping wavelength. The emission cross-section obtained from the Judd-Ofelt analysis and spectral data (4.9x10 −20 cm 2 ) is in fairly good agreement with the value obtained from the analysis of the laser threshold data (4x10 −20 cm 2 ).

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