X-ray free-electron lasers produce pulses of light that are exceptionally bright, making them powerful tools for studying ultrafast chemical reactions, biological processes, or probing the structure of materials at atomic scales. X-ray free-electron lasers produce pulses of light that are exceptionally bright, making them powerful tools for studying ultrafast chemical reactions, biological processes, or probing the structure of materials at atomic scales. Optics & Photonics Phys.org – latest science and technology news stories