Semiconductors have not only enabled discoveries of new physics but also realizations of vastly useful things that we cannot live without nowadays. Despite of the many successes and mature products, semiconductors are continuing to attract interest from research point of view, especially quantum and nano-structures and their applications in optoelectronics. In this talk I will outline some successful examples and more importantly the applications that they have enabled. Then I will discuss topics related to our research. The first one is, by now, the well-established quantum-well infrared photodetector (QWIP). Large focal plane arrays up to 1k×1k format and multi-spectral imaging sensors have been fabricated and used in space applications. High performance QWIP imagers are sold and used in various systems. QWIPs are also well suited for high-speed/high-frequency applications. I will discuss QWIPs being used in laboratories for high-speed/high-frequency infrared detection. The next topic is the development of high performance quantum cascade lasers (QCLs) in the mid-infrared region of about 4 to 11 mm as well as in the terahertz. Finally our recent collaborative work on QCL frequency comb generation will be presented, together with the potential for applications.
H. C. Liu （刘惠春） got his BSc in physics from Lanzhou University in 1982 and, via CUSPEA program, PhD in applied physics from the University of Pittsburgh in 1987 as an Andrew Mellon Predoctoral Fellow. Dr. Liu worked at the National Research Council of Canada from 1987 to 2011. Dr. Liu is currently a “1000” chair professor at the Shanghai Jiao Tong University. Dr. Liu has published extensively in refereed journal articles with an H-factor of 38. 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); 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) in 2005, and the Overseas Changjiang Scholar Award (MOE) in 2008.