Date and Time:  23-June-2022  15:00

Speaker:  Prof. Qijie Wang, Professor and the Associate Chair (Research) at School of Electrical and Electronic Engineering, Nanyang Technological University Singapore

Host: Quanyong Lu ( BAQIS）

Title: Quantum Cascade Lasers: Enabler for Mid-infrared and Terahertz Photonics

Abstract: 

Mid-infrared (MIR) and Terahertz (THz) spectral regions, hereafter defined as the ~3 – 300 μm wavelength range, hosts particular scientific and technological interests. Many molecules have strong and rich spectral fingerprints in this MIR region, therefore, MIR photonic and nanophotonic devices are potentially very promising for a breath of applications such as environmental and bio-chemical sensing, industrial control, and medicine, etc. THz region has wide applications in free space communication, imaging and spectroscopy. However, MIR and THz regions remain a far from mature region, with a dearth in both passive and active components.

In this talk, I am going to present the working principles and our achievements of MIR and THz quantum cascade laser, which is a semiconductor based electrical pumping source that can be designed to cover almost the whole MIR and THz regimes. I am going to talk about different types of quantum cascade lasers with beam collimation, polarization, and emission controls, particularly on our recent innovation on topologically protected electrically pumped THz QCLs that are robust to defects and sharp corners.

About the Speaker:

Professor Wang Qijie is a full professor and the Associate Chair (Research) at School of Electrical and Electronic Engineering, Nanyang Technological University Singapore. He also holds a joint appointment at School of Physical and Mathematical Sciences at the same University. His research field is in the mid-infrared and Terahertz Photonics. He has published/co-published more than 200 papers in top international journals (like Nature, Science, Nature Photonics, Nature Nanotechnology, Nature Materials, and Nature Communications). He was the recipient of the IES (Institution of Engineers Singapore) Prestigious Engineering Achievement Team Award of Singapore Twice in 2005 and 2017, respectively, 30th World Culture Special Recognition Award 2013, the prestigious Singapore Young Scientist Award 2014, and Nanyang Research Award NTU 2015. He was elected as fellow of Optical Society of America (OSA) in 2019.