Mechanical and Optical Sensing Using Plasmonic Nanoparticles

Dr Peter Zijlstra

Eindhoven University of Technology, Department of Applied Physics, The Netherlands

3:30 pm, Friday, 17 July 2015, EN102 Lecture Theatre (EN Building), Hawthorn

Metallic nanoparticles are attractive structures for nanosensing because they exhibit collective oscillations of their conduction electrons, so-called surface plasmon resonances. The presence of a plasmon resonance makes them easily detectable in an optical microscope, even down to the level of single particles. Here I will present two modes of sensing based on plasmonic nanoparticle: mechanical and optical sensing.
For mechanical sensing we exploit the sensitivity of the acoustic vibration frequencies to changes in the elastic constants and the dimensions of the particle. Deposition of material therefore causes changes in the acoustic vibration frequencies, which we detect by pump-probe spectroscopy. For optical sensing we use the sensitivity of the plasmon resonance to changes in the local refractive index. I will show recent results where we demonstrated a plasmonic sensor with single-molecule sensitivity based on a single gold nanorod.