Real-time and background-free detection of nanoscale particles.
We introduce a background-free real-time detection scheme capable of recognizing low-index nanoparticles such as single viruses in water. The method is based on interferometrically measuring the electromagnetic field amplitude of the scattered light. A split detector is used to generate a background-free signal that renders unprecedented sensitivity for small particles. In its current configuration the sensor is capable of detecting low-index particles in water down to 10 nm in radius or single gold particles as small as 5 nm. We demonstrate the detection of such small particles in a microfluidic system with a time resolution of 1 ms and we discuss the theoretical limits of this novel detection scheme.
The Institute of Optics, University of Rochester, Rochester, New York 14627, USA.
Filipp V
FV
Ignatovich
Lukas
L
Novotny
D009980:Influenza A virus / Q000737:chemistry; D007368:Interferometry / Q000379:methods; D007834:Lasers; D046210:Microfluidic Analytical Techniques / Q000379:methods; D049329:Nanostructures / Q000032:analysis* / Q000737:chemistry; D055095:Optics and Photonics; D012542:Scattering, Radiation