Monday, April 24, 2017 - 9:00am - 10:00am
George Schatz (Northwestern University)
This talk will overview the interplay between optics, plasmonics, and excitonics for systems that consist of arrays of gold, silver or aluminum nanoparticles in 1D, 2D and 3D. This will begin with a review of the use of classical electromagnetic theory to describe the optical properties of plasmonic particles of arbitrary shape, size and arrangement, and which leads to a variety of enhanced spectroscopies including surface enhanced Raman scattering.
Tuesday, March 14, 2017 - 2:00pm - 2:50pm
Andrew Norris (Rutgers, The State University of New Jersey)
First, I will discuss a now-classic topic but with some new twists: Transformation acoustics (TA), focusing on the special case of isotropic TA for which the required properties can be realized by a wide variety of homogenized structures. First, the ability of conformal mappings to yield highly accurate focusing lenses is described. These act via reciprocity as monopole to highly one-way-wave radiators. Second, matching to the exterior fluid places constraints on the TA map that are explored.
Wednesday, February 15, 2017 - 11:30am - 12:20pm
Shari Moskow (Drexel University)
We study the homogenization of a transmission problem arising in the scattering theory for bounded inhomogeneities with periodic coefficients modeled by the anisotropic Helmholtz equation. The coefficients are assumed to be periodic functions of the fast variable, specified over the unit cell with characteristic size epsilon. Using multiple scale expansion, we find bulk and boundary corrections to the leading-order (O(1)) homogenized transmission problem.
Wednesday, February 15, 2017 - 10:15am - 11:05am
Chris Xu (Cornell University)
Over the last two decades, multiphoton microscopy has created a renaissance in the brain imaging community. It has changed how we visualize neurons by providing high-resolution, non-invasive imaging capability deep within intact brain tissue. Multiphoton imaging will likely play an essential role in understanding how the brain works at the level of neural circuits, which will provide a bridge between microscopic interactions at the neuronal level and the complex computations performed at larger scales.
Thursday, November 3, 2016 - 3:15pm - 4:05pm
Svetlana Roudenko (George Washington University)
We discuss the focusing nonlinear Klein-Gordon equation starting with the cubic nonlinearity in 3 dimensions. Inspired by the paper of Donninger-Schlag on this equation, we further investigate the blow up and scattering behavior of its solutions. We extend the theoretical boundaries of the blow up regions and discuss the behavior of solutions there, for example, formation of a singularity away from the origin, and behavior near the ground and excited states. We also show extensions to other dimensions and nonlinearities.
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