Roland Kersting
— Assistant Professor of Physics
— Faculty of Information Technology
Rensselaer Polytechnic Institute

— Ph.D., Natural Sciences, Institute for Semiconductor Technology, Rheinisch Westfaelische Technische Hochschule (RWTH), Aachen, Germany, 1994
— Physics Diploma, Institute for Semiconductor Technology, RWTH, Aachen, 1990

Career Highlights:
Kersting joined the Rensselaer faculty in fall of 1999 as an assistant professor in the Department of Physics, Applied Physics, and Astronomy; a year later, he became a faculty member of Information Technology. Prior to his roles at Rensselaer, he spent a year as a researcher at the Institute for Solid State Electronics at the Technical University of Vienna, Austria, investigating terahertz (THz) excitation of intersubband transitions, and several months as a guest researcher studying THz semiconductor devices at the University of Nottingham, in the United Kingdom. He also held two postdocs at the University of Vienna and the Technical University of Vienna, Austria, each for two years. The first was at the Institute of Physical Chemistry, where he studied coherent and incoherent excitation transfer in polymers. At the Institute for Solid State Electronics, Kersting studied the generation of few-cycle THz pulses.

Research Areas:
Kersting's research within the Center for Broadband Data Transport Science and Technology involves THz photonics, a radical new concept for the development of ultrahigh speed devices. Terahertz photonics will give access to THz frequencies while still using standard semiconductor processing technology. Potential applications for terahertz photonics include ultrafast data communications and high speed Internet connects.

The conceptual idea is to use so-called 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.

THz photonics may allow switching rates of the order of 1 THz, and switching energies can be as small as 0.1 fJ, which allows for low power consumption and heat dissipation, even at THz frequencies. Also, the quantum energy of THz radiation (3 THz = 0.012eV) is orders of magnitude smaller than the quantum energy of near-infrared light signals (800 nm ~ 1.5 eV), which results in noise reduction. Current research focuses on silicon germanium devices, which will be highly compatible with standard semiconductor processing technology.

Selected Publications:
R. Ascazubi, O.C. Akin, T. Zaman, and R. Kersting, "Dephasing in Modulation-doped Quantum Structures Probed by THz Time-Domain Spectroscopy," Applied Physics Letters,
81, 4344, (2002).

A. Filin, M. Stowe, and R. Kersting, "Time-Domain Differentiation of Terahertz Pulses," Optical Letters, 26, 2008, (2001).

E. Gornik and R. Kersting, "Coherent THz Emission in Semiconductors," in Ultrafast Phenomena in Semiconductors, edited by K.T. Tsen. A volume of "Semiconductors and Semimetals," Treatise eds.: R.K. Willardson and E.R. Weber. 67, 389, Academic Press, (2000).

R. Kersting, G. Strasser, and K. Unterrainer, "THz Phase Modulator," Electrical Letters, 36, 1156, (2000).

R. Kersting, R. Bratschitsch, G. Strasser, K. Unterrainer, and J. Heyman. "Sampling a THz Dipole Transition with Subcycle Time Resolution," Optical Letters, 25, 272, (2000).

R. Kersting, K. Unterrainer, G. Strasser, H.F. Kauffmann, and E. Gornik. "Few-cycle THz Emission from Cold Plasma Oscillations," Physical Review Letters, 79, 3038, (1997).

Contact Information:
Roland Kersting
1C22 Jonsson-Rowland Science Center
Rensselaer Polytechnic Institute
Troy, N.Y. 12180
(518) 276-3092

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