报告摘要：

In this talk, I will first introduce the operation principle of QCLs. Then I will talk about what is the design difference between the mid-infrared and THz QCLs and the challenges. After that, I will introduce what we have done so far to improve the output power level, threshold current, and dynamic range of mid-infrared QCLs, and to achieve high temperature operation of THz QCLs. Performance with peak output power more than 1 W and slope efficiency of 1 W/A has been achieved for devices with an emission wavelength of 9 μm at room temperature. Devices emitting at a wavelength around 5 μm shows continuous-wave output power more than 1 W at room temperature with a single laser chip. In the end, a few applications of QCLs will be reviewed.

报告人简介：

Dr. WANG Qijie received the B.E. degree in electrical engineering from the University of Science and Technology of China (USTC), Hefei China, in 2001 graduating one year in advance; and the Ph.D degree in electrical and electronic engineering from Nanyang Technological University, Singapore, in 2005, with NTU and Singapore Millennium Foundation (SMF) scholarship. After completing his Ph.D, he obtained the 2005 SMF postdoctoral fellowship working in NTU. Then he joined School of Engineering and Applied Science, Harvard University, in Prof. Federico Capasso’s group as a postdoctoral researcher in Jan. 2007. In 2009, he was assigned as a joint Nanyang Assistant Professor at the School of Electrical and Electronic Engineering (Microelectronics Division) and the School of Physical and Mathematical Sciences (Physics and Applied Physics Division).
Dr. Wang has published/co-published more than 40 papers (including 3 invited papers) in top international journals (like Nature Photonics and Nature Materials), more than 40 conference papers (including a few invited talks) and co-authored 3 U.S. patents. He was the recipient of the top prize for the Young Inventor Awards of the SPIE Photonics Europe Innovation Village in 2004; a golden award from the Fifth Young Inventor’s Awards in 2005 organized by HP and Wall Street Journal; and the co-recipient of the IES (Institution of Engineers Singapore) Prestigious Engineering Achievement Team Award 2005 of Singapore.
His current research interests are to explore theoretically and experimentally nano-structured semiconductor and metal materials, and devices with an emphasis on all aspects of the problem: from design, fabrication, characterization, to integration at system level. In particular, he is going to investigate the fundamental properties (optical and electrical) of semiconductor lasers in both mid-IR (3-30 um) and Terahertz (60-300 um) frequency regimes to improve their performance. Exploration of their broad potential applications is also one of the key focuses.

光子技术研究所 2010年12月3日