Speaker：Prof.XIONG Qihua,Nanyang Technological University, Singapore
Time: 10:00a.m.Thursday,December 10
Place: A718 SINANO
Optical irradiation accompanied by spontaneous anti-Stokes emission can lead to cooling of matter, a phenomenon known as laser cooling or optical refrigeration proposed in 1929 by Peter Pringsheim. It was first experimentally demonstrated in rare-earth doped glasses with a recent record of ~100 K cooling from ambient, but attempts of laser cooling of semiconductors based on III-V quantum wells have led to minimum progress. In this talk, I will present our recent breakthrough of 40 Kelvin laser cooling of semiconductors in II-VI semiconductor nanoribbons. Recently, we have discovered another big family of materials, i.e., 2D and 3D organic-inorganic perovskite crystals for laser cooling.Our work advocates the great promises of optical refrigeration with the advantage of compactness, vibration- and cryogen-free, high reliability and direct integrability into nanoscale electronic and photonic devices.
Qihua Xiong received his B.S. degree in physics from Wuhan University in 1997, and then finished three years graduate studies at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. He went to the United States in 2000 and received a Ph.D. degree under the supervision of Prof. Peter C. Eklund from The Pennsylvania State University in 2006. After three years postdoctoral experience in Prof. Charles M. Lieber’s group at Harvard University,he joined Nanyang Technological University as an assistant professor in 2009 and promoted to Nanyang Associate Professor in 2014. He is a Fellow of Singapore National Research Foundation awarded in 2009. He has been recently awarded the prestigious Nanyang Award for research excellence and the NRF Investigatorship Award by Singapore National Research Foundation. Prof. Xiong’s research focuses on light-matter interactions of emergent quantum matter by optical spectroscopy approaches. He recently ventured into the field of 2D layered materials and laser cooling of solids.