CHROMATEM aims at developing original spectromicroscopy techniques combining photons and electrons for the study, at an unprecedented combination of energy and spatial resolutions, of low-dimensional physical phenomena and their applications in nanosciences, condensed matter physics, quantum technologies, health and environmental sciences. This pole is based on the long-standing renown and expertise of the Orsay group at LPS in spatially resolved electron energy-loss spectroscopy (EELS) and TEM instrumentation, and benefit from current developments on a Cs-corrected STEM (NION100 UltraSTEM). CHROMATEM target new problems that share the need to access the electronic and/or optical properties at the nanometer scale or at single atomic column positions with spectral resolutions not yet available at these spatial resolutions. This requires the implementation of an ultra-high resolution EELS spectrometer (now sub-5 meV proven on-site) in a Cs-corrected TEM with low-temperature capabilities, and the design of original instrumentation for light injection/detection. Our ambition is to develop new spectroscopies (ultra-high resolution EELS, nanometer-resolved cathodoluminescence, Electron Energy Gain Spectroscopy…) and explore new physical phenomena at the nanometer scale such as electronic phase transitions. Within collaborations with experts in their fields (sample production, bulk characterization or theory) CHROMATEM will address cutting edge issues, including metal-insulator transitions in systems with strong electronic correlations, photomagnetic mechanisms in molecular magnets, optoelectronic properties of semiconductor nanostructures, quantum nano-optics and interface physics in oxitronics and ferroelectric devices.