The International Year of Light

On 20 December 2013, the UN General Assembly proclaimed 2015 as the International Year of Light and Light-based Technologies (IYL 2015). The aim is to raise awareness about how these technologies provide solutions to global challenges in energy, education, agriculture and health.

In its quest to "see" the fundamental structure of matter, high-energy particle physics goes beyond the wavelengths of light to the wavelengths of particle beams. Over the years, developments in the accelerators that create those beams have led to new ways of producing light that have a big impact on other disciplines.

To celebrate the IYL 2015, this issue of CERN Courier looks at how brilliant, accelerator-based X-ray free-electron lasers are enabling exciting new studies in biology (see XFELs in the study of biological structure). Meanwhile, as Lucio Rossi points out in Viewpoint, accelerators provide the finest form of "light", and experiments can now "see" down to distances as small as 10–20 m (see Viewpoint). The High-Luminosity LHC project (see A luminous future for the LHC) will allow CERN’s collider to cast still more of this fine light on matter. Finally, Inside Story (see Inside story) looks at how light and particle physics came together in the life of one physicist.