A twist on thin-film technology may provide a way to optically detect and analyze multiple substances simultaneously, leading to quicker diagnostics in such industries as health care and homeland security, according to Penn State researchers.

One current optical-sensing technology can launch and guide a single light wave, called a surface-plasmon-polariton wave -- SPP wave -- that travels along the flat interface of the sample to be analyzed and a metal film. The SPP wave is launched by sending a light beam through a prism to the other face of the metal film. A photon detector eventually collects the beam that was reflected back into the prism. Any change in the optical properties of the sample critically alters the reflected beam.

The detector records this alteration, which analysts can then use as an optical fingerprint to help them identify the changes in the chemical composition of the sample, according to Akhlesh Lakhtakia, Charles Godfrey Binder Professor of Engineering Science and Mechanics.

However, because the technology allows for only one SPP wave of a certain frequency to be guided through the device, the properties of only one substance can be analyzed for each sensor, said Lakhtakia, who worked with Stephen Swiontek and Drew Pulsifer, both doctoral students in engineering science and mechanics.

Dr. Michael Lanagan, Professor in Engineering Science and Mechanics, was recently highlighted in a recent issue of Institute of Electrical and Electronics Engineers (IEEE) magazine on his work with Reconfigurable Antennas. Reconfigurable antennas change polarization, operating frequency, or far-field pattern in order to cope with changing system parameters. This paper reviews some of the past and current technology applicable to reconfigurable antennas with several examples of implementations. Mechanically movable parts and arrays are discused, as well as more recent semiconductor-component and turnable-material technologies applicable to reconfigurable antennas.

Dr. Osama Awadelkarim, Professor in Engineering Science and Mechanics, will travel to Medellin, Columni in March to serve as an invited speaker in the Columbia-U.S. Workshop on Nanotechnology. To learn more about the workshop, please visit their website.

Dr. Akhlesh Lakhtakia, Charles Godfrey Binder Professor in Engineering Science and Mechanics, will travel to San Diego, California in early March to co-chair the SPIE Conference. The conference is entitled Bioinspiration, Biomimetics, and Bioreplication III. To learn more, please visit their website.

Models of the human brain, patterned on engineering control theory, may some day help researchers control such neurological diseases as epilepsy, Parkinson's and migraines, according to a Penn State researcher who is using mathematical models of neuron networks from which more complex brain models emerge.

"The dual concepts of observability and controlability have been considered one of the most important developments in mathematics of the 20th century," said Steven J. Schiff, the Brush Chair Professor of Engineering and director of the Penn State Center for Neural Engineering. "Observability and controlability theorems essentially state that if you can observe and reconstruct a system's variables, you may be able to optimally control it. Incredibly, these theoretical concepts have been largely absent in the observation and control of complex biological systems."

Those engineering concepts were originally designed for simple linear phenomena, but were later revised to apply to non-linear systems. Such things as robotic navigation, automated aircraft landings, climate models and the human brain all require non-linear models and methods.