Lecturer: Dr. Yoav Lahini
Affiliation: Harvard University
Abstract:
High-speed tracking of single nano-
particles is an experimental challenge
whose realization could offer a
gateway to understanding fast
physical, chemical, and biological
processes occurring at the nanoscale.
Although methods such as confocal or
fluorescence microscopy offer both
high spatial resolution and high signal-
to-background ratios, they are limited
by the fluorescence emission lifetime,
and as a result cannot offer high-rate
measurements.
I will present a non-fluorescent, label-
free tracking method based on elastic
light scattering that enables
measurements of nanoparticle
dynamics and interactions at rates of
thousands of frames per second. The
particles are contained within a sub-
wavelength, nano-fluidic channel, that
is embedded in the light-guiding core
of a single-mode silica fiber. Using
this method we track unlabeled
dielectric particles as small as 20 nm
as well as individual cowpea chlorotic
mottle virus (CCMV) virions – 26 nm
in size and 4.6 megadaltons in mass –
at rates of over 3 kHz for durations of
tens of seconds. The coherence of the
scattering signal enabled
measurements of the interaction
between nanoparticles at very high
spatial and temporal resolution.