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Nanoscale Thermotropic Phase Transitions Enhance Photothermal Microscopy Signals
Language
en
Article de revue
This item was published in
Journal of Physical Chemistry Letters. 2012-04-30, vol. 3, n° 10, p. 1400
American Chemical Society
English Abstract
The photothermal heterodyne imaging technique enabled studies of individual weakly absorbing nano-objects in various environments. It uses a photo-induced change in the refractive index of the environment. Taking advantage ...Read more >
The photothermal heterodyne imaging technique enabled studies of individual weakly absorbing nano-objects in various environments. It uses a photo-induced change in the refractive index of the environment. Taking advantage of the dramatic index of refraction change occurring around a thermotropic liquid crystalline phase transition, we demonstrate a 40-fold signal-to-noise ratio enhancement for gold nanoparticles imaged in 4-Cyano-4'-pentylbiphenyl (5CB) liquid crystals over those in a water environment. We studied the photothermal signal as a function of probe laser polarization, heating power, and sample temperature quantifying the optimal enhancement. This study established photothermal microscopy as a valuable technique for inducing and/or detecting local phase transitions at the nanometer scales.Read less <
English Keywords
single molecule detection
Photothermal microscopy
nanoparticles
thermotropic phase transition
liquid crystals
single molecule detection.
Origin
Hal imported