Plasmonic nanosponges

Gold nanosponges, or nanoporous gold nanoparticles, possess a percolated nanoporous structure over the entire nanoparticles. The optical and plasmonic properties of gold nanosponges and its related hybrid nanosponges are very fascinating due to the unique structural feature, and are controllable and tuneable in a large scope by changing the structural parameters like pore/ligament size, porosity, particle size, particles form, and hybrid structure. The nanosponges show the strong polarization dependence and multiple resonances behavior. Besides, the nanosponges exhibit a significantly higher local field enhancement than the solid nanoparticles. Strong nonlinear optical properties are confirmed by their high-order photoemission behavior, whereby long-lived plasmon modes are also clearly observed. All this is very important and relevant for the applications in enhanced Raman scattering, fluorescence manipulation, sensing, and nonlinear photonics.