Optical Microcavities: Label-Free Detection Down to Single Virus Particles

Ongoing improvements in micro-and nanoengineering of optical materials allow the fabrication of photonic structures that confine light at exceedingly high quality factors. Examples for such miniature optical resonators are silica microspheres and defects in silicon photonic crystals. I will describe the application of optical microcavities for label-free biosensing. I will introduce the 'reactive' sensing principle which leverages a long photon lifetime for quantitative detection down to single virus particles. I will present several other experiments that use the high sensitivity of microsphere cavities in biophysical measurements: probing conformation of a photoreceptor, quantification of DNA hybridization, and optical characterization of a self-assembled monolayer. Then I will give an overview of sensing schemes and physical mechanisms that can further boost the current detection limit, possibly down to single molecules.

Bio:
Frank Vollmer is the principal investigator of the Biofunctional Photonics Group at the Rowland Institute at Harvard University, where he is a Rowland Junior Fellow. He received his Ph.D. in Physics in Biology from The Rockefeller University, New York, in 2004. His Ph.D. research, supervised by Professor Albert Libchaber, used optical resonators for ultra-sensitive biodetection, and applied physical principles and engineering methods to the problem of label-free molecular detection.