22-23-317
Paras N. Prasad, Distinguished Professor at the University of Buffalo – The State University of New York
Abstract
Chiral photonics dealing with light-matter interaction in Chiral media1, offers, via selective circular polarization (photon spin), spin control of both linear and nonlinear optical functions for applications ranging from optical switching, to negative- and near-zero refractive index metamaterials, to chiral bioimaging. It represents a new direction with substantial opportunity including secure optical communication, beam steering, all optical switching, signature control, quantum computing, bio-detection, subwavelength imaging, and brain wave detection to enhance human effectiveness. However, realization of such applications requires materials with optical activity at visible wavelengths that is orders of magnitude larger than that of any naturally occurring materials. Our theory-guided-design and synthesis of novel chiral polymers has yielded very large linear and multiphoton circular dichroism2. We have introduced the concepts of plasmonic, excitonic, and structural enhancement of linear and nonlinear multiphoton optical activities. Some results on polymers and nanocomposites exhibiting chirality derived large magneto-optic effect have also been achieved, which may enable mapping of ultra-weak magnetic fields, like those generated by brain function. We are pursuing multiscale modeling and experimental design of the interaction of structured light endowed with both spin and orbital angular momentum, with nanostructured chiral plasmonic media for adaptive control of effective dielectric function. The seminar will conclude with a discussion of challenges and opportunities in Chiral Photonics.
1. P.N. Prasad “Nanophotonics” John Wiley & Sons, (2004).
2. A. Baev, P.N. Prasad, H. Ågren, M. Samoć, and M. Wegener, »Metaphotonics: An emerging field with opportunities and challenges »; Physics Reports 594, 1-60 (2015).
