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Physics Colloquium Series: Professor Hayk Harutyunyan
(Physics Lecture Series) Department of Physics, Emory University
“Ultrafast and nonlinear nanophotonics”
The nanoscale confinement of materials opens up new possibilities for controlling and enhancing the light-matter interaction. The reduced dimensionality leads not only to novel electromagnetic phenomena but can also affect the nature of quantum transitions and ultrafast carrier dynamics. In this talk, I will present our latest efforts in the manipulation of light-matter interaction at the nanoscale using plasmonic, metamaterial and 2D material platforms. The first part of the talk will focus on the enhancement of the nonlinear optical effects at the nanoscale and the design of efficient nonlinear metasurfaces. The role of various factors such as field-enhancement, hybridization of resonances, mode symmetry and material properties will be considered. Next, I will discuss how the spatial localization of the electromagnetic fields can enable forbidden quantum transitions in materials. In particular, the enhancement of intraband absorption and hot carrier generation in gold through resonant Landau damping will be addressed. Finally, I will share our latest results on semiconductor metasurfaces where we demonstrate that the use of time- dependent material response can lead to some non-intuitive modification of fundamental properties of materials and observation of negative extinction.