University of California, Riverside

Department of Electrical and Computer Engineering



Light-Assisted Templated Self Assembly


Light-Assisted Templated Self Assembly
 
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Light-Assisted Templated Self Assembly

February 2, 2015 - 11:10 am
Winston Chung Hall, 205/206

Abstract
The force of light on objects provides tremendous flexibility in nanoscale manipulation, including the construction of nanomaterials “from the bottom up.” We have proposed and demonstrated a new technique that assembles and releases crystalline arrays of nanoparticles on demand. Unlike traditional colloidal self-assembly methods, which are limited by free energy constraints, our method is not limited to close-packed structures and can be used to form a variety of 2D crystalline lattices. 

Our method, called light-assisted templated self assembly (LATS), uses a resonant electromagnetic mode of a photonic crystal to enhance the intensity of an incident laser beam, providing a regular array of strong optical traps. Turning the laser on and off will reversibly assemble or disassemble the structure, while changing the laser wavelength or polarization allows different crystal lattices to be formed. For weakly-interacting particles such as polystyrene, we demonstrate that we can form large, ordered arrays of over 100 closely spaced particles. For strongly-interacting particles such as gold, we observe that multi-particle interactions drive the emergence of 1D features within the 2D optical potential. We observe the formation of self-stabilizing particle chains with an orientation that can be controlled with polarization. Moreover, by changing the underlying symmetry of the template, the effects of interparticle interactions can be neutralized, leading to the formation of periodic, gold nanoparticle arrays. 

Our method, ideally suited for on-chip integration, should provide a platform for flow-through, serial fabrication of 2D or 3D-nanostructured materials, all-optically tunable photonic devices, and lab-on-a-chip applications. 

Biography

Dr. Michelle Lynn Povinelli is an Associate Professor in the Ming Hsieh Department of Electrical Engineering at the University of Southern California. She received a BA from the University of Chicago, an MPhil from the University of Cambridge, and a PhD from MIT, all in Physics. She was a postdoctoral researcher in Electrical Engineering at Stanford University, where she won a L'Oréal For Women in Science Postdoctoral Fellowship. She is the recipient of an NSF CAREER Award, Army Research Office Young Investigator Award, Presidential Early Career Award for Scientists and Engineers (PECASE), and a TR35 Award. She has co-authored over sixty journal articles and three book chapters. 

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University of California, Riverside
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Electrical and Computer Engineering
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University of California, Riverside
Riverside, CA 92521-0429

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