Subject：THz Quantum Devices (太赫兹量子器件)

Lecturer：Prof. H. C. Liu（National Research Council of Canada）

Time：June 22, 2009 （Monday）2: 30pm

Place：Transient Optics Department 3F meeting room

Prof. H. C. Liu

H. C. Liu (刘惠春) got his BSc in physics from Lanzhou University and PhD in applied physics from the University of Pittsburgh in 1987 as an Andrew Mellon Predoctoral Fellow. Dr. Liu is currently the Imaging Devices Group Leader in the Institute for Microstructural Sciences at the National Research Council of Canada. Dr. Liu has authored and co-authored over 300 refereed journal articles (with about 90 first or sole authored), and given 111 talks (70 invited) at international conferences. He has been elected as Fellows of the American Physical Society (APS), of the Institute of Electrical and Electronics Engineers (IEEE), and of the Academy of Sciences – Royal Society of Canada (RSC); granted over a dozen patents; awarded the Herzberg Medal from the Canadian Association of Physicists in 2000, the Bessel Prize from the Alexander von Humboldt Foundation in 2001, the Chinese Overseas Distinguished Young Scientist Award (NSFC-B) in 2005, and the Overseas Changjiang Chair Professorship at the Shanghai Jiao Tong University in 2008.

Abstract

Terahertz (THz) science and technology are widely investigated nowadays. To have a wide spread application, the key components, namely detectors and lasers, must be available, with the following properties: compact, convenient, and mass producible. Unfortunately today’s commercial THz detectors have various drawbacks such as low sensitivity, slow speed, and needing deep cryogenic cooling. THz quantum cascade lasers (QCL) have only been realized in 2002. Though impressive advances in THz QCLs have been achieved, the operating temperature is still in the cryogenic regime. Quantum structures based on semiconductors offer new possibilities. This talk starts with a general overview of various quantum structure THz detectors and then list some applications where THz lasers are needed. I will review the current status of THz QCLs. The main part of the talk is on new directions in using either quantum dots and impurities for new THz lasers with potentially superior performance.