A steady-state thermoreflectance method to measure thermal conductivity

Area of Science:

• Materials Science
• Thermal Physics
• Optical Spectroscopy

Background:

• Accurate measurement of thermal conductivity is crucial for material design and performance.
• Existing techniques may have limitations in terms of material range or experimental complexity.

Purpose of the Study:

• To present and validate a novel optical pump-probe technique for determining thermal conductivity.
• To demonstrate the applicability of the method across a broad spectrum of materials.

Main Methods:

• Utilizing a continuous wave laser to induce a steady-state temperature rise (pump beam).
• Employing a probe beam to measure surface reflectance changes, correlating to temperature variations.
• Applying Fourier's law, combined with varying pump power, to calculate thermal conductivity.

Main Results:

• The developed steady-state thermoreflectance technique successfully measured thermal conductivity.
• The technique demonstrated accuracy for materials with thermal conductivities from 1 to over 2000 W m⁻¹ K⁻¹.
• Experimental results showed excellent agreement with established literature values.

Conclusions:

• The steady-state thermoreflectance pump-probe method offers a versatile and accurate approach for thermal conductivity measurements.
• This technique is suitable for a wide range of materials, facilitating materials characterization.
• The method provides a reliable alternative for thermal property evaluation in scientific research.