Terahertz for Broadband Research

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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