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.
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.
Assistant Professor, Department of Physics
Rensselaer Polytechnic Institute
110 8th Street
Troy, NY 12180-3590
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