The past several decades have seen huge advances in the speeds at which electronics operate. Consumer electronics, such as computers, currently operate at gigahertz speeds and market forces continue to push for even greater speed. Roland Kersting's study of terahertz (THz) photonics, a novel concept for information processing using THz pulses switched at THz speeds, offers tremendous promise to fulfill this insatiable appetite for high-speed data communications.

Many techniques have been developed for generating and detecting THz pulses, yet the devices to process these signals – the THz information technology – remain less developed. Kersting's lab is working on the development of this technology – the modulators and switches – with ongoing research aimed at developing non-linear switches, considered the next step in THz information technology. To date, Kersting has developed a THz modulator and THz time-domain differentiator 10,000 times faster than anything currently available in electronics.

Kersting explains that the beauty of THz photonics is that the proposed devices can be fabricated using existing semiconductor technology. THz pulses will propagate on metallic transmission lines, eliminating the need for hybrid technologies. One limitation of THz photonics is the low integration density of devices on a chip, yet numerous applications for THz photonics within high-speed data communications remain.

Technical Description:
Efficient THz devices require an extremely strong coupling between the THz electromagnetic pulses and the material of the devices. Semiconductor heterostructures, with their gigantic dipole moments and extremely small switching energies, provide an outstanding material.

Kersting's group is working on the fabrication of THz heterostructure devices in the cleanroom facilities at the THz center. The fabricated devices are characterized by exciting them with ultra-fast THz signals, then measuring their response directly in time-domain. Kersting's lab has demonstrated modulators and resonances as high as 3.0 THz as well as THz differentiators, which give instantaneous derivative in time-domain of incoming signals.

Contact Information:
Roland Kersting
Assistant Professor, Department of Physics
Rensselaer Polytechnic Institute
110 8th Street
Troy, NY 12180-3590

(518) 276-3092