Date:

Wednesday, September 26, 2018

Time:

Map to P&A

ADA accommodations will be provided upon request. 

The notions of nonreciprocal properties in both photonics and materials have received significant traction recently, given their technological implications. Nonreciprocity can arise due to asymmetric property tensors, nonlinearity and spatio-temporal modulation.  However, it can be enhanced in non-Hermitian as well as topological settings. For instance, many important properties of materials such as the optical diode effect depend on the interplay between the concepts of reciprocity, chirality and broken spatial and temporal symmetries. I will illustrate these concepts through a number of examples including non-reciprocal directional dichroism.  Specifically, I will discuss the conditions for non-reciprocity of ferro-rotational order in several materials and indicate the use of linear optical gyration and possibly vortex beams as a likely way to detect ferro-rotational domains.  The concept of vector order parameters will be then generalized to second- and higher-rank tensor order parameters.  Finally, I will elucidate how to achieve high-temperature optical diode effect. Part of this work was performed in collaboration with S.-W. Cheong (Rutgers Univ.), D. Talbayev (Tulane Univ.) and V. Kiryukhin (Rutgers Univ).

 Brief biography: 

Avadh Saxena is Group Leader of the Condensed Matter and Complex Systems group (T-4) at Los Alamos National Lab, New Mexico, USA, where he has been since 1990. He is also an affiliate of the Center for Nonlinear Studies at Los Alamos. His main research interests include phase transitions, optical, electronic, vibrational, transport and magnetic properties of functional materials, device physics, soft condensed matter, geometry, topology and nonlinear phenomena. He is an Affiliate Professor at the Royal Institute of Technology (KTH), Stockholm, Sweden and holds adjunct professor positions at the University of Barcelona, Spain, Virginia Tech and the University of Arizona, Tucson. He is Scientific Advisor to National Institute for Materials Science (NIMS), Tsukuba, Japan. He is a Fellow of Los Alamos National Lab, a Fellow of the American Physical Society (APS), and a member of the Sigma Xi Scientific Research Society and APS. Contact him at: avadh@lanl.gov

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