Xi-Cheng Zhang of Rensselaer Receives Distinguished IEEE Award for Influential Terahertz Research
Xi-Cheng Zhang, the J. Erik Jonsson ’22 Distinguished
Professor of Science and director of the Center for Terahertz
Research at Rensselaer Polytechnic Institute, has received the
William Streifer Scientific Achievement Award from the IEEE
Photonic Society. The award honors Zhang for his exceptional
contributions in the past 10 years to the field of lasers and
“Dr. Zhang’s work is literally changing the way in which we
can see the world and all that it is made of,” said Rensselaer
Acting Dean of Science David Spooner. “His research and
development of terahertz technology has broken new ground in
the field of photonics time and again and has implications for
science, industry, law enforcement, and even counter-terrorism
efforts. We are exceptionally proud of his many
The award is given for a single, recent contribution to
photonics that has greatly influenced the research community.
Zhang was cited “for the exceptional contribution of terahertz
air photonics, especially free-space coherent detection of
ultra-broadband terahertz waves.”
Terahertz (THz) waves occupy a segment of the
electromagnetic spectrum between the infrared and microwave
bands. As such, they can be used for imaging and sensing in
ways that are not possible with conventional technologies such
as X-ray and microwave. Because THz radiation transmits through
almost anything that is not metal or liquid, the waves can
“see” through most materials that might be used to conceal
explosives or other materials, such as packaging, corrugated
cardboard, clothing, shoes, backpacks, and book bags. They are
also safer than X-rays and microwaves for human tissue.
The vast potential of terahertz-based technology has been
understood for years, but the development of practical
applications of THz was greatly limited by something as simple
as air. Ambient moisture in the air outside of a highly
regulated lab environment blocks THz wave transmission. This
made it nearly impossible to apply THz technology outside the
controlled lab setting up until now.
Zhang’s development of THz air photonics has resulted in the
discovery of several important THz techniques:
- THz Air-Biased-Coherent-Detection (THz ABCD). Instead of
fighting with the properties of the air, the technology
developed by Zhang works with it. This technique uses air and
selected gases as the THz wave emitter. A focused optical
pulse creates atmospheric plasma, which produces very strong
and ultra-broadband THz waves.
- THz-Enhanced Acoustics (TEA) and THz-Enhanced
Fluorescence (TEF). The development of remote, spectroscopic
sensing technologies for THz waves are lagging behind
important real-world needs such as the detection of
explosives in airport baggage. Zhang and his students have
developed THz-enhanced acoustic (TEA) and THz-enhanced
fluorescence (TEF) techniques with standoff sensing
capability. By “hearing” THz-enhanced acoustics (TEA), or
“seeing” THz-enhanced-fluorescence (TEF), coherent detection
of THz waves at standoff distance has been achieved.
- Control of THz Wave Polarization. Zhang and his team
developed a unique method to harness THz wave polarization.
The polarization of THz pulses emitted from a laser-generated
air-plasma can be rotated by changing the relative delay
between ultra-short two color (red and blue) pulses.
Zhang joined Rensselaer in 1992. He received his bachelor’s
in physics from Peking University in China and both a master’s
and doctoral degree in physics from Brown University. He is a
fellow of the American Physics Society, the Institute of
Electrical and Electronic Engineers, and the Optical Society of
America. He is an NSF CAREER Award winner who has been featured
in more than 80 magazines, 28 books and book chapters, and 300
journal papers. He holds 26 U.S. patents.
The Technology Review listed Zhang’s work in as one
of “10 Emerging Technologies That Will Change World” in 2004.
The History Channel and Discovery Channel have interviewed
Prof. Zhang for their Modern Marvels and The
Greatest Gadget programs. Zhang’s instrument development
was also selected as one of the “Scientific American
50” in 2008.
More information of the Center for Terahertz Research can be
found at http://thz.phys.rpi.edu.
Contact: Gabrielle DeMarco
Phone: (518) 276-6542