Nonequilibrium Polariton Thermometry enabled via Infrared Variable Angle Spectroscopy Ellipsometry
Abstract
PI-Hopkins requests support for the purchase of an Infrared Variable Angle Spectroscopic Ellipsometer Ð the IR-VASE Mark II from J.A. Woollam. This proposed equipment will offer unprecedented measurement, resolution, and identification of infrared active energetic modes through a robust technique that offers the chemical sensitivity of FTIR spectroscopy with the thin film sensitivity of spectroscopic ellipsometry. Covering a wide spectral range from 1.7 to 30 microns (333 to 5900 wavenumbers), the IR-VASE will be used to characterize bulk materials, optical constants (n and k and dielectric constants À1 and À2), film thickness, material composition, chemical bonding via molecular vibrations, phonon absorption, interfacial layers and free carrier absorption, which will enhance and offer new directions to current and future programs that are funded by the Army Research Office and the DoD. The integration of this proposed equipment, in both ex-situ and in-situ fashions, will enable new regimes in experimental diagnostics, and thus redefine the current state-of-the-art in measurement and understanding of these coupled and energetically nonequilibrium processes driven from IR photon interactions, such as novel phononpolariton processes of interest to current ARO programs. The IR-VASE microscope capability will characterize the IR properties of coupled modes the near dielectric, semiconductor, and metal interfaces, permitting a new understanding of local field and electrostatic boundary condition effects on IR-active vibrational and polaritonic modes. By coupling the modulated IR pump-probe laser with the high-speed and broadband step-scan measurement system of the IR-VASE, we will be able to observe spectral shifts of plasmons, phonon-polaritons, and molecular vibron modes during pulsed laser heating, which would be otherwise not possible to observe, thus enabling new fundamental understanding to be gained. Thus, the acquisition of this IR-VASE equipment will enable novel experimental development to interrogate the femtosecond relaxation dynamics of highly nonequilibrium vibrational modes coupled with IR energies in nanoscale materials and interfaces. In addition to significant and numerous impacts on DoD programs and technologies, the instrument will play an important role in the education and training of graduate and undergraduate students in thermophysical property measurements, instrumentation science, and material transport. The proposed instrument, which has an estimated lifetime of ~25 years, will complement existing infrastructure, providing capabilities that will substantially impact DoD programs and technologies of interest to the United States.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 27, 2022
- Source ID
- W911NF2210029
Entities
People
- Patrick Hopkins
Organizations
- Army Contracting Command
- United States Army
- University of Virginia