Angle-resolved and time-resolved spectroscopic study on large-area silver gratings fabricated via optical interference lithography

Abstract

Plasmonic resonators, which can enhance the near-field due to plasmon excitation, have attracted extensive research interest due to their significant potential in photodetection, photocatalysis, photovoltaics, and other applications. Here, we experimentally present spectroscopic results of plasmonic resonances on large-area nanoscale silver (Ag) gratings, fabricated by optical interference lithography based on angle-resolved optical absorption spectroscopy and femtosecond transient absorption spectroscopy (TAS). Specifically, we have measured plasmon resonances as a function of azimuthal angles and detection angles under p- and s-polarization. TAS reveals the non-radiative decay of plasmon resonances by transferring energy to nearby species, including exciting plasmonic hot electrons, which can be harvested by coupled semiconductors through a metal-semiconductor Schottky barrier. Our numerical simulation provides insight into the near-field analysis and quantifies the density of plasmonic hot electrons excited in our Ag-gratings.