Dayan Ban

Professor, Electrical and Computer Engineering

Research interests: terahertz; quantum cascading lasers; nanophotonics; nanofabrication; SPM


Professor Dayan Ban was one of the leading researchers who developed and prototyped the first wafer-fused infrared optical up-converter and the first pixelless infrared optical up-conversion imaging device. He also pioneered the research in scanning probe microscopy and invented scanning differential spreading resistance microscopy technique.

Ban and his group are currently investigating how to improve the device efficiency of hybrid organic/inorganic devices, experimentally measure the active-region temperature of lasing terahertz quantum cascade lasers, directly observe thermal lasing quenching of terahertz quantum cascade lasers, and apply time-domain terahertz spectroscopy to study the device physics of terahertz quantum cascade lasers.

At the National Research Council’s Institute for Materials Science, Ban and his colleagues demonstrated terahertz (THz) quantum-well-cascade lasers with lasing wavelength at 104 micrometers (~2.9 THz in frequency) and experimentally studied the doping effect in THz quantum cascade lasers –€“ pinpointing the balance between free carrier absorption loss and optical gain. Ban was a visiting scientist at Nortel in 2001-2002, where he and his colleagues developed and applied novel scanning probe microscopy techniques. The nano-probing techniques were deployed to observe two-dimensional profiles of the electrical potential and conductivity within actively driven devices, with nanometer spatial resolution.


  • PhD, University of Toronto, 2003

  • MSc, University of Science and Technology of China, China, 1995

  • BSc, University of Science and Technology of China, China, 1993

Dayan Ban


Converting near-infrared light directly to visible light

Professor Ban joined the Department of Electrical and Computer Engineering at the University of Waterloo in 2005. Since that time, Dr Ban’s group has successfully fabricated prototype hybrid organic/inorganic devices by direct tandem integration and studied the effects of interfacial states on device performance. The devices convert near-infrared light directly to visible light (green) at room temperature.

Designing and fabricating high-performance quantum devices

Professor Ban’s group has been designing, fabricating and characterizing terahertz quantum cascade lasers in pursuit of high-temperature, high-power operation. The terahertz quantum cascade lasers can be used for terahertz spectroscopy, terahertz imaging (T-Ray) and free-space optical communication, which have significant impacts on environmental, biological, medical applications, homeland security, and communication.

Developing ultra-sensitive surface plasmon sensors

Professor Ban’s group is collaborating with other colleagues to develop a compact sensing system that is based on surface plasmon resonance. This system integrates the advanced terahertz technology with a surface plasmon system so as to take advantage of both to offer ultra high sensitivity, high portability and operability. Applications of this system include detection of antibodies and antigens in clinical diagnosis and medical analysis.

Research interests

  • Terahertz quantum cascade lasers

  • Nanotechnology, nanomaterials, nanodevices

  • Scanning probe microscopy

  • Semiconductor quantum devices