The objective of this research effort is to develop plasmonic mid-infrared sensors based on epitaxially deposited silver films. The approach is to utilize the extraordinary optical transmission through arrays of sub-wavelength holes in a metal. Surface plasmon polaritons supported by such hole arrays are responsible for the extraordinary Optical transmission, and are highly sensitive to the refractive index of the surrounding medium or analyte. A recently discovered phenomenon of the omni-directional photonic bandgap will be utilized. To enhance the effect, atomically smooth metal films will be grown on various substrates. The omni-directional nature of the gap enables focusing light on an ultra-small (one wavelength across) sensor.
If successful, the benefits of this research will include the development of novel tools for analyzing ultra-small amounts of multiple analytes for disease detection using mid-infrared sensing. The mid-infrared part of the spectrum is critically important for sensing applications because chemical composition of large and complex molecules can be revealed through their mid-infrared optical "fingerprints". These sensing techniques could potentially revolutionize label-free detection of biological and chemical substances. Future optical sensing devices should also be capable of processing minute amounts of analyte, and do so in a very dense format of small closely spaced sensors. The project will include significant outreach to high school, undergraduate, and graduate Hispanic students in Texas. High school students from local schools will conduct summer research in PI's laboratories, collaborate with graduate students, and receive mentorship from the recently established Mentorship Networks among minority students in the San Antonio/Austin area aimed at enhancing the interest and awareness of nanoscale science among minority students.
