Title: From Lead Halide Perovskites to Lead-Free Metal Halide Perovskites and Double Perovskites: Insights from Density-Functional TheorySpeaker:Yanfa Yan (Professor, Department of Physics and Astronomy, and Wright Center for Photovoltaic Innovation and Commercialization, The University of Toledo, United States)

Time: May 28, 2018 10:00AM

Venue:No. 101 meeting room of the library, IOS, CAS

Abstract: Monolithic subwavelength gratings (MSG) can be implemented in any material with a real refractive index larger than 1.75 without the need of the combination of low and high refractive index materials enabling total reflectance or total transmittance depending on geometrical parameters. It has an application potential in passive and active optoelectronic devices, but mostly it has great prospects in application to monolithically integrated Vertical-Cavity Surface-Emitting Lasers (VCSELs).
I will show that:
-        MSG simplifies the VCSEL construction from hundreds of layer to only few
-        MSG can be integrated with metals facilitating the dual function of an emission mirror and a current injector in VCSELs.
-         MSG facilitates transparent contacts
-        MSG enables strong interaction of resonating light with surroundings making VCSEL a sensing device requiring no detector
-         MSG solves 20 years old problem of vertical resonance in quantum cascades

Biography：Tomasz Czyszanowski received his M.Sc. and Ph.D. degrees in physics from Lodz University of Technology, Poland, in 2000 and 2004 respectively, and a D.Sc. degree in physics from Wroclaw University of Technology, Poland, in 2012. After receiving his M.Sc. he was a visiting researcher at CFD Research Corporation, Huntsville, Alabama, where he worked mainly on optical scalar models of semiconductor lasers. His Ph.D. work involved studies on the validity limits of approaches to optical fields in diode lasers. From 2005 to 2007 he was a post-doctoral researcher at Vrije University, Brussels, Belgium, on a fellowship awarded by the Foundation for Polish Science. There he analyzed the performance of photonic-crystal VCSELs. In 2012 he was appointed Associate Professor at the Institute of Physics at Lodz University of Technology, Poland. His current area of research involves the modeling subwavelength gratings, VCSELs with gratings and VCSEL arrays. He has authored or co-authored more than 60 articles and three book chapters.