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

Area of Science:

• Materials Science
• Thermal Physics
• Spectroscopy

Background:

• Accurate measurement of transient thermal properties is crucial for advanced materials.
• Existing techniques often lack sufficient temporal or spatial resolution.
• Raman spectroscopy offers non-contact material characterization capabilities.

Purpose of the Study:

• To develop a new transient Raman thermal probing technique.
• To measure the thermal diffusivity of materials with high resolution.
• To validate the technique using a microscale silicon cantilever.

Main Methods:

• Development of frequency-resolved Raman (FR-Raman) technique.
• Utilizing an amplitude-modulated square-wave laser for heating and excitation.
• Reconstructing Raman property evolution (intensity, wavenumber, emission) against frequency.
• Fitting the data to determine thermal diffusivity.

Main Results:

• Successfully measured the thermal diffusivity of a silicon cantilever using FR-Raman.
• Obtained consistent thermal diffusivity values (9.02–11.00 × 10⁻⁵ m²/s) from different Raman properties.
• Demonstrated good agreement with existing literature values.

Conclusions:

• FR-Raman is a viable novel method for transient thermal probing.
• The technique provides excellent temporal and micrometer-scale spatial resolution.
• FR-Raman has potential applications in diverse material characterization.