Frequency-resolved Raman for transient thermal probing and thermal diffusivity measurement

Journal Article · Fri Dec 18 04:00:00 UTC 2015 · Optics Letters

DOI: https://doi.org/10.1364/OL.41.000080 · OSTI ID:1357249

Wang, Tianyu ^[1]; Xu, Shen ^[1]; Hurley, David H. ^[2]; Yue, Yanan ^[3]; Wang, Xinwei ^[1]

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1. Iowa State Univ., Ames, IA (United States)
2. Idaho National Lab. (INL), Idaho Falls, ID (United States)
3. Wuhan Univ., Hubei (China)

Steady state Raman has been widely used for temperature probing and thermal conductivity/conductance measurement in combination with temperature coefficient calibration. In this work, a new transient Raman thermal probing technique: frequency-resolved Raman (FR-Raman) is developed for probing the transient thermal response of materials and measuring their thermal diffusivity. The FR-Raman uses an amplitude modulated square-wave laser for simultaneous material heating and Raman excitation. The evolution profile of Raman properties: intensity, Raman wavenumber, and emission, against frequency are measured experimentally and reconstructed theoretically. They are used for fitting to determine the thermal diffusivity of the material under test. A Si cantilever is used to investigate the capacity of this new technique. The cantilever’s thermal diffusivity is determined as 9.57 × 10^-5 m²/s, 11.00 × 10^-5 m²/s and 9.02 × 10^-5 m²/s by fitting the Raman intensity, wavenumber and emission. The deviation from the reference value is largely attributed to thermal stress-induced material deflection and Raman drift, which could be significantly suppressed by using a higher sensitivity Raman spectrometer with lower laser energy. As a result, the FR-Raman provides a novel way for transient thermal characterization of materials with a ?m spatial resolution.

• Research Organization: Idaho National Lab., Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: AC07-05ID14517
• OSTI ID: 1357249
• Report Number(s): INL/JOU--15-35835
• Journal Information: Optics Letters, Journal Name: Optics Letters Journal Issue: 1 Vol. 41; ISSN 0146-9592; ISSN OPLEDP
• Publisher: Optical Society of America (OSA)Copyright Statement
• Country of Publication: United States
• Language: English