title: High sensitivity nanoparticle detection using optical microcavities.
abstract: We demonstrate a highly sensitive nanoparticle and virus detection method by using a thermal-stabilized reference interferometer in conjunction with an ultrahigh-Q microcavity. Sensitivity is sufficient to resolve shifts caused by binding of individual nanobeads in solution down to a record radius of 12.5 nm, a size approaching that of single protein molecules. A histogram of wavelength shift versus nanoparticle radius shows that particle size can be inferred from shift maxima. Additionally, the signal-to-noise ratio for detection of Influenza A virus is enhanced to 381 from the previously reported 31. The method does not use feedback stabilization of the probe laser. It is also observed that the conjunction of particle-induced backscatter and optical-path-induced shifts can be used to enhance detection signal-to-noise.
authors: Department of Applied Physics, MC 128-95, California Institute of Technology, Pasadena, CA 91125, USA. taolu@ece.uvic.ca
authors: Tao
authors: T
authors: Lu
authors: Hansuek
authors: H
authors: Lee
authors: Tong
authors: T
authors: Chen
authors: Steven
authors: S
authors: Herchak
authors: Ji-Hun
authors: JH
authors: Kim
authors: Scott E
authors: SE
authors: Fraser
authors: Richard C
authors: RC
authors: Flagan
authors: Kerry
authors: K
authors: Vahala
mesh_terms: D015374:Biosensing Techniques; D006801:Humans; D009980:Influenza A virus / Q000302:isolation & purification; D007368:Interferometry / Q000379:methods; D053758:Nanoparticles; D010316:Particle Size; D011137:Polystyrenes; D012680:Sensitivity and Specificity; D014771:Virion / Q000302:isolation & purification; D014780:Viruses / Q000302:isolation & purification*
chemical_list: D011137:Polystyrenes