Enhanced second harmonic generation in a plasmonic particle-in-cavity nanoantenna

Abstract

© 2016 IEEE.Plasmonic nanostructures that support surface plasmon resonances potentially provide a route for the development of nanoengineered nonlinear optical media. A strong enhancement of second harmonic generation (SHG) in a particle-in-cavity nanoantenna (PIC-NA) is proposed and theoretically demonstrated in this work. The fundamental and second harmonic responses of the PIC-NA are calculated using a self-consistent boundary element method. Through a comparison with the linear field enhancement spectra, the SHG from PIC-NA is boosted by the strongly enhanced fundamental and SH fields arising from the cascaded focusing of large optical energy into the small gap. The proposed 3D plasmonic PIC-NA functions as the new synthetic second-order nonlinear optical material that has promising applications in the nonlinear sensing, spectroscopy and frequency generating.