Integrated hybrid plasmonic cavity with in-plane photon-plasmon coupling for luminescence enhancement

摘要

A device consisting of a disk-shaped, Moiré-type plasmonic cavity placed inside a plasmonic crystal cavity, with a 250nm polymethyl-methacrylate (PMMA) film over the cavities is analyzed by 3D finite-difference time domain (FDTD).Both cavities can be fabricated by Focus Ion Beam, and the waveguide and the Moiré cavity contour can be defined byone-step lithographic process. The device is characterized by calculating the cavity spectrum, the reflection and theradiation spectra and the electric field intensity distribution. It was verified that the transverse-magnetic (TM) inputmode generates surface plasmon polaritons (SPP) at the PMMA/gold interface that excites localized surface plasmonpolariton on the Moiré cavity, that, in turn, generates reflected waves back to the waveguide and diffracted radiation.Also, the lack of plasmonic crystal bandgap permits the evanescent coupling of Bloch waves to the plasmonic crystal.The high electric field generated by the LSPP on the Moiré surface, and by the Bloch waves at the borders of theplasmonic crystal holes, contributes to the fluorescence of molecules dissolved in the PMMA film. The radiatedfluorescence can be detected by a lensed fiber placed above the Moiré surface, and the reflected signal can be detected atthe output.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.