FTIR Spectrometer with Integrating Sphere for Phonon and Infrared Photon Properties Characterizations
Abstract
Heat conduction is important in thermoelectrics, thermal management, electronics, and other applications. At the atomic scale, lattice thermal conductivity is governed by phonon dispersion and relaxation times of both acoustic and optical phonons. On the other hand, infrared thermal radiative properties are important in coatings, thermal radiation management, photovoltaics, and optoelectronics applications. At the atomic scale, infrared thermal radiative properties of polar materials are governed by frequencies and relaxation times of optical phonons (that is why these phonons are called “optical” phonons). Thermal conductivity and radiative properties of these associated materials, though seemingly unrelated, have in common an underlying phonon root. The PI has several DOD projects including AFOSR MURI and DARPA projects on heat conduction involving high thermal conductivity materials (for thermal management) and low thermal conductivity materials (for thermoelectrics). With the proposed FTIR spectrometer, the PI will be able to measure the infrared spectra of innovative materials, in order to validate the phonon frequencies and scattering rates predicted from the various modeling methods. The PI also has had two AFOSR projects related to thermal radiative properties of coatings especially based on carbon nanotubes. The radiative properties in the UV-visible-near infrared have been extensively studied by his UV-Vis-NIR spectrometer and integrating sphere. With the proposed FTIR spectrometer and integrating sphere, he will be able to extend such measurements to far-infrared wavelength up to 30?m. This wavelength range is important for many DOD applications such as coatings. The proposed equipment will also enable the PI to perform research in the area of radiative cooling by measuring the spectral reflectance in the sky window (8-13 ?m). Radiative cooling is promising for cooling outdoor electronic equipment.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 09, 2018
- Source ID
- FA95501710368
Entities
People
- Xiulin Ruan
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Virginia