Raman spectroscopy for thermal transport characterization: Principles, techniques, and applications

Raman thermometry converts temperature-dependent spectral shifts into quantitative temperature fields, enabling noncontact measurement of heat transport across a wide range of materials and length scales. This Tutorial presents a unified and practical framework that couples heat-diffusion physics with spectroscopic temperature readout in steady-state and transient regimes. The governing heat equations are developed explicitly for experimentally relevant geometries, including supported and suspended films, multilayer structures, granular media, and particle-laden composites, allowing readers to adapt the models to specific sample structures and boundary conditions. The Tutorial also provides detailed methodological guidance for Raman thermometry in biological and soft-matter systems, addressing experimental configurations and heat-transport considerations in hydrated and heterogeneous environments. A key distinction of this work is its unified treatment of phonon-mediated and photon-mediated heat transport. Representative case studies demonstrate the extraction of intrinsic nanoparticle and interfacial thermal properties from composite measurements and the experimental quantification of near-field radiative heat transfer in densely packed nanoparticle assemblies. Together, these elements establish Raman thermometry as a versatile and quantitative platform for nanoscale thermal characterization across solid-state, granular, and biological systems.