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| Collaborative Research with Physics Department We work with Professor Edward Nadgorny (Physics) on development and application of a novel Laser-Based Particle Deposition (LBPD) technique that is capable of patterning of porous microstructures made of nanoparticles:
The technique uses laser-induced optical forces to transport liquid droplets or particle-in-liquid droplets from a supply source and deposit them on a substrate mounted on a translation stage. A variety of structures (porous and non-porous) can be constructed on different substrates using metals, dielectrics, semiconductors, piezoelectric and ionic crystals, as well as living cells and proteins. Unlike well-known optical trapping techniques, the LBPD technique utilizes optical transverse gradient forces to confine particles inside weakly focused laser beams and take advantage of radiation pressure and absorption force to move particles axially. An optical trap, on the other hand (sometimes referred to as an optical tweezer) makes use of a strongly focused laser beam with a very strong axial gradient to allow axial trapping.
A 120-micron-wide pattern made of 7 nm gold-thiolate nanoparticles and ended with a bare gold electrode (J. Xu, 2002)
"Blackberry" - cluster of 100 nm polystyrene particles, diameter of the cluster is about 1 micron (J. Xu, 2001)
"Question Mark" - 400 nm polystyrene particles coated with 100 nm polystyrene particles (J. Xu & O. Mills, 2001)
Parallel 40 micron strips made of ~20nm gold particles (J. Xu, 2001)
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