Above: Resonance wavelenth shifts 17fm with interaction of the BSA protein particle. A shift in wavelength corresponds to the energy needed to polarize the protein, and thus determine its mass to attogram (10e-18g) precision.
Right: Comsol simulation of the signal enhancement factor X at the hotspot of a gold/silica nanoshell antenna, located on the microsphere sensor’s equator.
Whispering Gallery Mode structures will sustain an echo almost indefinitely because specific geometries are matched to the sound energy wavelength. The same effect occurs in microscopic spheres interacting with light waves.
Left: Grand Central Station WGM. Center: Diagram of primary mode structure in a spheroid. Right: A microscopic WGM sensor and fiber optic. Dark line is a tapered fiber, dots of light are detected analyte particles in solution.
Research
Transmission Electron Micrograph of gold/silica nanoshells with their natural rough surface. Right: Theoretical diagram used to perform calculations.
Above: Signal enhancement factor R (first order dipole expansion) for surface textures on a gold nanoshell antenna, mounted on a micro-sensor.
Above: Our lab wrote theory for this new production-feasible silicon WGM biosensor.
Right: Sub-nanometer lythography tolerances are required for sensor fabrication. Plot of
SNR loss vs. placement error, calculated by theory and directly by monte-carlo simulation.