Events

"Optical Nanostructures for Enhanced Light-Matter Interactions and Energy Harvesting"

Dr. Debashis Chanda, Beckman Institute, University of Illinois at Urbana-Champaign

February 16th (Thursday), 8:30am
Engineering Science Building (ESB), Room 2001


The talk will focus on the design and development of high throughput, large scale and low cost fabrication of optical nanostructures for enhanced light-matter interactions in artificially structured metal/dielectric structures (metamaterials, plasmonic nanostructures), strong coupling between photonic and plasmonic resonances and trapping light in thin film solar cells. We are currently pursuing approaches based on proximity field nanopatterning, soft nanoimprint lithography and nanotransfer printing patterning techniques. In their current forms, these methods can produce diverse classes of 3D and quasi-3D nanostructures with excellent structural uniformity and small features sizes. Their operational characteristics avoid practical challenges in patterning speed and area coverage associated with established techniques such as electron and focused ion beam lithography. In one example, we developed a nanotransfer printing based fabrication approach to large-area, high-quality negative index metamaterials (NIMs) with three-dimensional layouts with throughputs and areal coverage that are approximately one hundred million times higher than those possible with conventional techniques. Measurements and simulations show expected negative index behaviors, with figures of merit that exceed those of small samples fabricated in the usual way. In other work, we used soft nanoimprint lithography to create structures with plasmonic responses that couple strongly to modes of integrated, asymmetric Fabry-Perot cavities. We demonstrated that this arrangement can exhibit highly enhanced or diminished reflection properties, effectively like a narrow band absorber, but in a way that can be tuned reversibly using the techniques of opto-fluidics. We also developed wave optics light trapping schemes to enhance light absorption in thin-film silicon solar cells and demonstrated cell efficiency of >10% in just 2.8┬Ám thick c-Si cells.

About Dr. Debashis Chanda:

Dr. Debashis Chanda is a post-doctoral fellow with Prof. John A. Rogers at Beckman Institute, University of Illinois at Urbana-Champaign since 2009. His present work involves advancing fundamental understanding of light-matter interactions in artificially structured metal/dielectric structures (metamaterials, plasmonic nanostructures), transformation optics for display/camouflage, strong coupling between photonic and plasmonic resonances and trapping light in thin film solar cells. Some of these works appeared as cover article (Nature Nanotechnology, Laser Focus World) in quite a few press releases and news coverage (MIT Tech Review, Physics Today, Nanotechweb, Physics.org etc). Dr. Chanda received his PhD from University of Toronto working with Prof. Peter Herman where he developed a diffractive optics lithography based high throughput laser fabrication technique of large area fabrication of 3-dimensional photonic crystals. The work was recognized in the form of several awards, including prestigious National Sciences and Engineering Research Council (NSERC) fellowship. Before that he worked for ABB and Philips research labs for couple of years each on optical/RF communications and opto-electronics component design projects.

Hosted by: Professor John Bowers