THORS: Thermally-induced Optical Reflection of Sound
Our group has discovered a method of optically exciting air (or other media) to generate localized thermal boundaries capable of efficiently reflecting and guiding acoustic waves without the need for solid physical barriers present. Current research efforts in this area revolve around thoroughly characterizing this novel phenomenon we call THORS as well as applying it to: enhanced standoff photoacoustic sensing of trace species, acoustic shielding and enhanced photoacoustic imaging in condensed matter (e.g., tissues and water).
Multiphoton Photoacoustic Spectroscopy for Sub-Surface Chemical Imaging of Tissues
Using multi-photon excitation of endogenous chemical species in tissue via near infrared light, followed by photoacoustic detection, sub-surface imaging and margining of brain tumors is possible.
SERS Nanoimaging
Using a tapered surface enhanced Raman scattering (SERS)-based fiber optic imaging bundle it is possible to obtain dynamic, chemical images of microscopic objects (~ 20 microns) with sub-50 nm spatial resolution. We are applying this technique to image in real-time the dynamics of cellular surface and lipid raft events in a label-free manner.
Intracellular Nanosensors for Pre-Symptomatic Disease Monitoring
Using surface enhanced Raman scattering (SERS)-based optical nanosensors coupled with optical tweezers-based positioning and multi-spectral imaging, we are able to monitor real-time protein expression and biochemical pathway activation as well as provide a means of pre-symptomatically monitoring disease state progression.
Understanding Plasmonics and Nanophotonics
The ability to generate controlled nanoscale structures has resulted in entirely new fields of optical sensing, including “plasmonics”. Although surface enhanced Raman scattering (SERS) has been around since the 1970s, constant developments in its application to sensing arise. One such discovery has been the significant enhancements in SERS associated with the application of alternating layers of metal and dielectric, known as the multilayer effect. Since discovering this phenomenon in our lab in the early 2000s, we have been using it to providing orders of magnitude improvement in chemical sensing platforms of various architectures as well as studying the fundamental physical parameters controlling this additional enhancement to SERS, as compared to comparable single layered plasmic substrates.
