On Tuesday March 21st, Professor Aleksandar D. Rakić from The University of Queensland arrived at SUSTech, presenting an attractive lecture to the students and staff. We were glad to have such a famous scientist visit SUSTech and share his latest research with everyone interested in the development of electrical engineering. Firstly, the professor delivered a speech concerning a new method for laser-feedback, “Interferometer”, which was welcomed by the audience. He also introduced the “3+1+X” project with junior and senior students in a nice atmosphere. Finally, with the accompaniment of Professor Chen of the Electrical Engineering Department, he visited the research laboratory. The whole day’s visit was a big success. Without a doubt, with his wisdom and kindness, Professor Rakić made the visit a perfect chance to enhance the interaction between SUSTech and the University of Queensland.
During his lecture, Professor Rakić mainly spoke of the laser-feedback interferometry technology with the use of QCL and its important application in a variety of fields. At the start, the professor proposed his work of utilizing the self-mixing phenomenon in QCLs to research laser-feedback interferometry. It is known that the Quantum Cascade Laser (QCL) is a dramatically useful and innovational technique which attracts more and more attention. Over the past decade however, the QCL has established itself as one of the most promising radiation sources for imagining applications at THz frequencies due to its ability to generate coherent continuous-wave emission with quantum noise-limited linewidths. This makes THz QCLs particularly suited to the development of coherent THz sensing and imaging systems. Owning these unique properties, QCL has become a solid choice for laser-feedback interferometry and THz imaging and sensing. In this scheme of laser-feedback interferometry using QCL, a portion of the emitted beam is coupled back into the laser cavity after reflection from an external target. Optical retro-injection affects the laser’s operating parameters; in particular, the laser emission frequency and the laser compliance voltage. By exploiting the interferometric nature of optical feedback in a THz QCL, the laser effectively becomes a highly sensitive and compact homodyning transceiver. Furthermore, the professor presented some recent advancements in the development of coherent THz imaging and sensing systems based on laser-feedback interferometry. These examples also included imaging and tissue analysis of excised porcine and murine tissue. In simple and precise language, Professor Rakić explained the basic principles of the use of QCL in laser-feedback interferometry, providing a new and effective way for THz imaging and sensing. With warm applause, the audience expressed their thanks and admirability. Indeed, this was a beneficial and splendid speech!
Aleksandar D. Rakić leads the Photonics and Microwave Engineering group at The University of Queensland focusing on the development of technologies for sensing and imaging across the electromagnetic spectrum, including microwave, terahertz wave, and optical systems. His current focus is on the development of sensing and imaging systems exploiting the terahertz spectrum for applications from security and defense to in-vivo biomedical imaging. His other principal contributions relate to the design and characterization of surface-emitting optoelectronic devices (VCSELs and light emitting diodes). He served as the General Chair of the 2004 “Conference on Optoelectronic and Microelectronic Materials and Devices" (COMMAD ‘04), as Co-Chair of the "Symposium on Molecular and Organic Electronics and Organic Displays" within the 2006 International Conference on Nanoscience and Nanotechnology (ICONN 2006), as Chair of the “Symposium on Compound Semiconductor Materials and Devices" within the 2008 International Conference on Electronic Materials (ICEM 2008) and as Chair, IEEE AP/h17T Queensland Chapter. He is currently Professor of Photonics within the School of Information Technology and Electrical Engineering, at The University of Queensland.