Rare earth ions are nowadays regarded as one of the most versatile luminescent systems capable of producing light in a wide spectral range covering from the depth UV up to the medium infrared with a quantum efficiency almost reaching 100%. They, indeed, have been the basis of past solid state lasers that still play a relevant role in medicine, industry and science.



During the last few years, rare earth ions, through its luminescence, are being used as optical probes capable of giving us information at the micro and sub-micrometric scale when combined with high resolution confocal fluorescence microscopy.



In this talk Professor Daniel Jaque (Universidad Antonoma de Madrid) will briefly explain the basic principles and mechanisms of rare earth fluorescence, paying special attention to the information that fluorescence provides about the ion's environment. He will show some very simple examples about how the presence of rare earth ions opens an unexplored window to understand and control the physics of micro luminescent systems. The examples shown cover from material science (fluorescence imaging of ultrafast laser written photonic devices in crystals and chalcogenide micro-spheres) up to live sciences (cancer cell imaging).