Study of small-scale radiative heat transfer in multi-body systems using a platform of local thermoresistive probes

Overview & Synopsis

This thesis presents the development and use of an experimental platform dedicated to the study of radiative heat transfer at the microscale in multi-body configurations. Based on local thermometric probes integrated with metrological Wheatstone bridges, the platform enables the detection of radiative heat fluxes on the order of picowatts, with sub-micrometer spatial resolution under high-vacuum conditions.We first validate the setup by investigating heat transfer in a sphere–plane geometry. The measurements reveal a non-monotonic variation of the exchanged flux with distance, an effect directly linked to spectral redistribution induced by the substrate. These results are consistent with theoretical predictions and are supported by full-wave numerical simulations using the SCUFF-EM code.We then implement a novel two-probe configuration forming a sphere–sphere geometry. This setup enables, for the first time, simultaneous local temperature measurements on both bodies in a two-sphere system. The results reveal asymmetric flux behavior that strongly depends on the environmental temperature, demonstrating the key role of three-body effects in radiative heat transfer. A simple analytical model is developed to reproduce and explain these observations.Thanks to its high sensitivity, stability, and active signal modulation, the platform also opens the way to near-field measurements in more complex geometries. The results presented in this thesis constitute the first experimental demonstration of multi-body effects in radiative heat transfer at the microscale and pave the way for advanced studies in nanoscale thermal transport, radiative energy conversion, and thermal logic.