Advances in photothermal and photoacoustic metrology.

The absorption of electromagnetic radiation by fluids or solids results in a temperature change, which, in turn, causes a change in volume resulting in the generation of a mechanical wave. When the emitted acoustic waves are recorded, the effect is referred to as a photoacoustic or optoacoustic effect. Many of the modern thermal measurement methods rely on photothermal and photoacoustic effects, including thermoreflectance, Raman scattering, Brillouin light scattering, and thermal radiation. Using two different photothermal techniques, micro-Raman thermometry and scanning thermal microscopy, Massoud I et al. i [6] measured the thermal conductivity of porous silicon, showing that both methods yielded consistent results. [Extracted from the article]