1School of Physics, Nanjing University, Nanjing, China
Impurities usually play an important role in modifying the bulk properties of electronic or electromagnetic materials. Very recently, a “doping” effect of impurities in epsilon-near-zero media has been proposed . In this talk, I will first demonstrate how to use the doping discipline to control the absorption of light so as to realize geometry-invariant coherent perfect absorption (CPA). Such a CPA has been experimentally verified in microwaves. Secondly, I will demonstrate a way to break the doping discipline and realize the extraordinary property of impurity-immunity  (photonic “anti-doping” effect) by using parity-time symmetry. In this case, the system exhibits the rare property of perfect transmission irrespective of embedded impurities of almost any materials and shapes.
 I. Liberal, A. M. Mahmoud, Y. Li, B. Edward, N. Engheta, “Photonic doping of epsilon-near-zero media,” Science 355, 1058 (2017).
 J. Luo, B. Liu, Z. H. Hang, Y. Lai, “Optical “anti-doping” effect induced by Parity-Time symmetry”, accepted in Laser & Photonics Reviews (2018).
 J. Luo, J. Li, Y. Lai, “Electromagnetic impurity-immunity induced by parity-time symmetry,” submitted.
Prof. Yun Lai obtained his PhD from Hong Kong University of Science and Technology (HKUST) in 2005 and has been a Research Associate in HKUST until 2011. From 2011 to 2017, he has been a Professor and the Vice Dean of the School of Physical Science and Technology in Soochow University. In 2018, Prof. Lai joined the School of Physics in Nanjing University as a Professor.
Prof. Lai has published more than 60 papers on SCI journals including Nature Materials, Nature Communications, Physical Review Letters, etc. His works has been cited by more than 2000 times and has been highlighted by Science, Nature, Nature Materials, Discovery Channel, Wall Street Journals, etc. Prof. Lai has been enrolled in the first patch of Thousand Youth Talents Program in China.