Quantitative Models of Light-Matter Interactions in Highly Excited Semiconductors
Abstract
This research supports Air and Space Force requirements for mid-wave infrared light detectors and lasers to increase capabilities in image and data capture and transmission for applications in surveillance, communications, target discrimination, and autonomous navigation. A database of optical constants (refractive index and absorption coefficient) as a function of wavelength and temperature (10 to 800 degrees Kelvin) will be established for infrared materials, especially semiconductors with a small band gap, based on measurements using spectroscopic ellipsometry from the mid-infrared to the near ultraviolet spectral region. The optical constants will be described by theoretical models with a small number of parameters based on the electronic band structure. The models will be adjusted as needed to take into account non-parabolic and warped bands and the attraction of the electron-hole pairs generated by the light absorption (excitons). Specific emphasis will be placed on the modifications of the optical constants (reduced absorption coefficient) under very high charge densities due to high levels of impurity doping, high temperature, and high-power ultrafast laser excitation. Results will be applied to materials of high specific relevance for mid-wave infrared detectors, such as indium antimonide, silicon-germanium-tin alloys, and indium-gallium-arsenide-antimonide alloys. This project will support graduate and undergraduate students, contributing to the development of a skilled work force in optoelectronics meeting the needs of several AFRL directorates (RV, RD, RY, RX) and other government laboratories. Students will gain international experience by performing experiments at a European user facility in Prague, Czech Republic. Results will be disseminated at conferences, in peer-reviewed journal articles, and in online databases.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 05, 2025
- Source ID
- FA95502410061
Entities
People
- Stefan Zollner
Organizations
- Air Force Office of Scientific Research
- New Mexico State University
- United States Air Force