Mapping the Electromagnetic Near Field of Gold Nanoparticles in Poly(methyl) Methacrylate
Engerer, Kristin Jean
As electronic and optical devices shrink to the nanoscale, accurate methods for characterizing electromagnetic fields generated by sub-wavelength structures become increasingly important. Absorption in poly(methyl methacrylate) (PMMA) via 4th harmonic generation in metallic nanostructures is a way to characterize complex resonance modes. When exposed with a femptosecond Ti:sapphire oscillator, the damaged PMMA surrounding the nanoparticles can be imaged with an scanning electron microscope, creating an electric near-field intensity profile. This occurs without absorbing the fundamental frequency, and provides an accurate visualization of the resonant fields. Localized surface plasmonic near-fields generated by metallic nanorods have been mapped previously with this technique. In this document, nanorods and bowtie antennas are fabricated and the electric near-field intensity imaged with PMMA mapping. We then analyzed this data to determine more about the technique and about what drives the resonance of plasmonic nanoantennas.