HDR DEFENSE of Jean-Paul GUILLET - November 28, 2025

« This HDR summarizes my research activities on terahertz (THz) waves from 2010 to today, with a focus on bringing THz technologies from fundamental studies to application-ready systems. The work covers a broad range of use cases—art and cultural heritage analysis, biomedical imaging (notably breast cancer), industrial non-destructive testing, agronomy, and petrology—through THz imaging and spectroscopy. Experimentally, more than ten complementary techniques have been developed or integrated (THz-TDS, FMCW radars, near-field imaging, tomography, computational imaging, guided reflectometry). These systems are supported by dedicated data-processing methods, enabling 3D reconstruction, fast full-field imaging, and sub-wavelength or sub-resolution thickness measurements. In parallel, specific THz components such as waveguides, multi-beam antennas and silicon-based circuits have been designed to overcome current technological limitations. An open-source platform has been initiated to ease access to millimeter-wave sensors and THz imaging, fostering reproducibility and technology transfer. Looking ahead, the project aims at massively parallel, intelligent, real-time THz imaging systems, embedded in a connected and interoperable “computational terahertz” framework and supported by strong academic and industrial collaborations » – Jean-Paul Guillet.