报告摘要：

The terahertz (THz) radiation band of the electromagnetic spectrum lies between the microwave and infrared regions, and as such represents the meeting point between electronic and optical technologies. Although it has been challenging to bridge this technological “gap”, THz radiation has many highly attractive properties for sensing applications, including the ability to detect important gases within the Earth’s atmosphere and in deep space. It also has far wider potential in imaging technology, including the detection of drugs and explosives, and in probing the behaviour of semiconductor devices, medical diagnostics, and in biochemical and pharmaceutical compounds.

While conventional THz sensors have been based on complex and large (bench- or room-sized) systems, a relatively new device—the Quantum Cascade Laser (QCL)—has enabled the development of powerful, yet compact THz sensor systems, with the prospect for deployment in satellite, industrial or clinical applications.

In this talk, I shall discuss recent progress at Leeds in the development of THz-QCL systems for atmospheric research and imaging. Compact, integrated THz receivers are being developed for satellite-based studies of the Earth’s upper atmosphere. Based on the self-mixing (SM) effect, these systems have been used to obtain “detector free” gas spectroscopy. I shall also show how the SM effect can be used to generate high-resolution images and in near-field microscopy, without requiring any external detector.

报告人简介：

Dr. Alexander Valavanis is a UK Research and Innovation “Future Leaders” Fellow (Tenure Track) at the University of Leeds, UK. His research focuses on the development of terahertz-frequency (THz) systems for atmospheric and space research. His research group has expertise in the theory, design, fabrication and applications of quantum-cascade laser (QCL) technology.

His research has been recognised through awards including the IET Electronics Letters Premium Award (2015) for developing the world-record-holding highest-powered THz QCL, the BNFL Peter Wilson Award (2009) for Materials Engineering research, and the GW Carter (2008) and FW Carter (2009) prizes for his PhD research at Leeds.

He is currently leading two UK Space Agency contracts, to develop high-precision THz QCL systems for satellite applications, including the proposed LOCUS atmospheric sounder system (“Linking Observations of Climate the Upper Atmosphere and Space Weather”). His other activities include the development of self-mixing (detector free) THz gas spectroscopy systems and optimised THz optics. His long-term vision is to develop THz instrumentation that will address key scientific challenges, including the study of star and planetary formation processes, and the analysis of chemical processes underpinning climate-change phenomena in the upper atmosphere.

“论坛”主请人联系方式：

王迎新  wangyingxin@tsinghua.edu.cn