Thermal diffusivity determination using heterodyne phase insensitive transient grating spectroscopy
Name
JAP-Ge-TGS-Accepted.pdf
Description
Main article after revisions
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2.37 MB
Format
Adobe PDF
Checksum (MD5)
174621ab360e89a5439760c1252e278c
Author(s)
Dennett, Cody Andrew
Short, Michael P
Date Issued
June 2018
Journal
Journal of Applied Physics
Citation
Dennett, Cody A., and Michael P. Short. “Thermal Diffusivity Determination Using Heterodyne Phase Insensitive Transient Grating Spectroscopy.” Journal of Applied Physics 123, no. 21 (June 7, 2018): 215109.
Version
Author's final manuscript
Abstract
The elastic and thermal transport properties of opaque materials may be measured using transient grating spectroscopy (TGS) by inducing and monitoring periodic excitations in both reflectivity and surface displacement. The “phase grating” response encodes both properties of interest, but complicates quantitative analysis by convolving temperature dynamics with surface displacement dynamics. Thus, thermal transport characteristics are typically determined using the “amplitude grating” response to isolate the surface temperature dynamics. However, this signal character requires absolute heterodyne phase calibration and contains no elastic property information. Here, a method is developed by which phase grating TGS measurements may be consistently analyzed to determine thermal diffusivity with no prior knowledge of the expected properties. To demonstrate this ability, the wavelength-dependent 1D effective thermal diffusivity of pure germanium is measured using this type of response and found to be consistent with theoretical predictions made by solving the Boltzmann transport equation. This ability to determine the elastic and thermal properties from a single set of TGS measurements will be particularly advantageous for new in situ implementations of the technique being used to study dynamic materials systems.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1063/1.5026429
