Plasmonic nanomechanical transduction

In this thesis, we investigate the interaction between light, confined to the nanoscale in the form of surface plasmon polaritons, and the motion of micro- and nanomechanical oscillators. Taken together, these form plasmonic optomechanical systems. The strong field confinement and local field enhancement around plasmonic antennas make them extremely sensitive transducers of mechanical motion to scattered optical fields. Due to the strong field gradients in the plasmonic near field the optomechanical coupling constant G can exceed 1 THz/nm, which is well beyond that of other existing mechanical transduction geometries.
We show that plasmonic nanostructures can be used to transduce thermally driven nanomechanical motion to optical signals. Plasmonic antennas show very high coupling rates, combined with small physical sizes and sub-wavelength mode volumes. These properties make plasmonics an interesting platform for motion transduction, allowing free space coupling and parallel transduction of nanoscale mechanical motion.