Enhancing the electromagnetic radiation of swift charged particles & dipoles

报告人： Dr. Xiao Lin, School of Physical and Mathematical

Sciences, Nanyang Technological University, Singapore

时间：2019年1月17日，13:30-14:30

地点：复旦大学兴业光学楼525

联系人：孙树林

Abstract: Our work aims to explore the novel scheme of manipulating the electromagnetic radiation from a moving source in a flexible way, by using metamaterials/metasurfaces, 2D materials and photonic crystals. (1) When the source is the high-energy charged particle, one of the ways to identify it is to use Cherenkov detectors. For the past several decades, this relied on measuring the Cherenkov radiation emitted from a conventional radiator material like helium, fluorocarbon gas, aerogel etc. The Cherenkov radiation from such materials is described by the theory developed by Frank and Tamm in the 1930’s. Here we propose a new mechanism, i.e., the constructive interference of resonance transition radiation from artificial nanophotonic systems, for creating novel kinds of Cherenkov radiators. This may overcome the current limits of particle identification and expand our abilities to enhance the momentum range of the high-energy particles that can be identified. (2) When the source becomes to have a natural frequency such as a moving dipole, an inverse Doppler frequency shift of light, i.e., superlight inverse Doppler effect, is revealed possible in homogeneous positive-refractive-index materials, contrary to the status quo ante. This further develops Ginzburg and Frank’s theory of superlight Doppler effect and Veselago’s theory of inverse Doppler effect. (3) Finally, some other exotic electromagnetic phenomena, such as superscattering and anomalous transition radiation beyond the formation time, will be discussed.

Short Biography: Dr. Xiao Lin is a research fellow at the Division of Physics & Applied Physics, Nanyang Technological University (NTU), Singapore, under the supervision of Prof. Baile Zhang. He received the bachelor’s degree in Optical Engineering in 2011, and Ph.D. in Electronic & Information Engineering in 2016, both from Zhejiang University. He visited Marin Soljacic’s group at the Department of Physics, MIT, as a joint Ph.D. student during September, 2015 to August, 2016. His research interests primarily include free-electron radiation (e.g., Cherenkov radiation, transition radiation), the active manipulation of near-field light-matter interactions, and exotic electromagnetic phenomena (e.g., superlight Doppler effects, superscattering, negative refraction), by using the platform of metamaterials/metasurfaces, 2D materials or photonic crystals. He, as first or co-first author, has published papers in high-profile journals such as Nature Physics (2 papers), PRL, PNAS, and Science Advances. His works have been highlighted by Nature Photonics twice and picked up as the Editor’s suggestion in PRL.