Friday, July 28, 2023

Thomas Folland 2
Tom Folland

The National Science Foundation has awarded Assistant Professor Tom Folland and Professor John Prineas a $411,378 grant to develop long wavelength infrared detectors that can measure atmospheric chemicals using optical antennas.

The detection of long wavelength infrared light can help scientists monitor environmental and engineering processes which are part of societal challenges such as climate change. Long wavelength infrared cameras can be used for non-contact imaging of temperature changes, as all materials near room temperature naturally emit light within this wavelength range.

These detectors are also used for detecting changes in chemical composition in the atmosphere, as many different chemicals we wish to detect possess a spectral signature in this wavelength range. However, developing semiconductor detectors and cameras that operate at long wavelengths has been a major technological challenge. This is largely as long wavelength light is associated with very low energy photons, which are detected by narrow energy gap semiconductors. These semiconductors are susceptible to noise and require cryogenic coolers to operate efficiently, making them expensive and bulky.

John Prineas
John Prineas

This research project “Phonon Polariton Based Infrared Optoelectronics” will address these problems by developing detectors that integrate optical antennas, which both enhance the amount of light that can be captured by the detector and reduce noise sources. Specifically, it will develop antennas that use the natural vibrations of crystals, known as surface phonon polaritons, which offer a means to trap light extremely efficiently to the detector. The objective of the research is to realize detectors with improved noise performance operating at higher temperatures, which will increase the scalability of infrared technologies for myriad applications.

This program will also engage rural communities in Iowa with semiconductor nanotechnologies through two related programs. Specifically, through the Junior Science and Humanities symposium, we will tour high school students around the Iowa semiconductor cleanroom facilities and discuss careers in semiconductor science and technology. We will also work with the UI Pentacrest museums to develop a video exhibit, introducing both the scientific concepts we are exploring, as well as the technological implications of our work.