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The terahertz range
of frequencies is often referred to as the "terahertz
gap," since its range falls in between those of electronic
and photonic devices. Members of the Center's Terahertz for
Broadband team are working to close this gap by conducting
innovative research for THz frequency use for broadband applications.
They are focusing on THz wave generation, detection, sensing,
and imaging applications. This research will rely on silicon
germanium technology developed at IBM.
Tomographic imaging applications, time-domain
THz spectroscopy systems, THz wave imaging involving "functional
images," and THz photonics are among the exciting areas
of study underway in the center. Accomplishments by Center
members include successfully building demonstration prototypes
of THz-speed electronic devices, as well as conducting promising
diagnostics research involving time-domain THz spectroscopy
systems.
Members' studies of T-rays for 3-D tomographic
imaging applications involve modifying system hardware for
imaging larger targets at longer distances, developing better
algorithms for reconstruction, 3-D identification of materials,
and demonstrating Fresnel binary lens for improved THz imaging.
The work with time-domain THz spectroscopy
systems holds promise for diagnostics of materials such as
semiconductors and biomolecules. THz time-domain spectroscopy
uses short pulses of broadband THz radiation, typically generated
using ultrafast laser pulses. The transmitted THz electric
field is measured coherently, which provides both high sensitivity
and time-resolved phase information.
Their THz wave imaging work involves functional
images, which are ideal for dry dielectric substances including
paper, plastics, and ceramics. This research focuses on 2-D
THz wave imaging through free-space electro-optic detection
and on THz ray, or T-ray, imaging for probing the dielectric
properties of 3-D structures.
Center researchers are successfully building
demonstration prototypes of THz-speed electronic devices – a
feat accomplished by just a few groups in the world. Their
technique involves THz photonics, a radical new concept for
ultrahigh speed device development. This field will give access
to THz frequencies, while still using standard semiconductor
processing technology. Potential applications for this technology
include ultrafast data communications and high speed Internet
connects. The concept uses few-cycle THz pulses as information
units. These ultrafast far-infrared pulses can propagate on-chip
along metallic transmission lines. As in optical photonics,
signal processing at THz frequencies can be achieved by amplitude
or by phase manipulation in conjunction with nonlinear switching.
Photonics in this band has not been addressed intensively,
although THz radiation can be generated by current all-solid
state techniques.
For more information on the Center's work
on Terahertz for Broadband, please contact:
Dr. Michael Shur, Director
(518) 276-2201
shurm@rpi.edu
Photonic
Links | Remote Internet Measurement
Laboratories
Terahertz for Broadband | Wide
Band Gap Semiconductors
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