  We demonstrate the selective control of the magnetic response and
photoluminescence properties of Er3+ centers with light, by associating them
with a highly conjugated beta-diketonate (1,3-di(2-naphthyl)-1,3-propanedione)
ligand. We demonstrate this system to be an optically-pumped molecular compound
emittingin infra-red, which can be employed as a precise heat-driving and
detecting unit for low temperatures
