plasmon-enhanced optical transmission at multiple wavelengths through an asymmetric corrugated thin silver film

Micro- and nanometallic structures that exhibit extraordinary optical transmission (eot) have attracted much attention for their potential applications in photonic devices. however, most existing reports have only discussed eot at one specific wavelength, which limits its use in multi-wavelength applications. here, we experimentally demonstrate eot at multiple wavelengths through an asymmetric corrugated thin silver film due to simultaneous excitation of multiple plasmonic resonances at both interfaces. a unique method that applies single-pulse nanosecond laser interference lithography is introduced to produce the silver grating, which shows high quality over large area. at oblique incidence, each eot peak is observed to split into two peaks oppositely shifted towards higher and lower frequencies. at some specific angles of incidence, overlap of these shifted peaks gives rise to distorted transmission spectra. our method find applications involving multiple wavelengths such as multi-wavelength bandpass filters, anti-stokes raman scattering spectroscopy, enhanced four-wave mixing, and so on.