Finer Control from an X-ray Laser

A new laser emits coherent pulses at the short X-ray wavelength of 1.46 nm—in energy terms, that’s in the kiloelectronvolt regime. Nina Rohringer from the Center for Free Electron Laser Science at the Deutsches Elektronen Synchrotron (Germany) and others reported creating the high-energy laser with gain by population inversion, which provides femtosecond-duration as well as high-intensity X-ray pulses with narrower emission wavelengths, better wavelength stability and improved temporal coherence compared with X-ray free-electron lasers (Nature 481, 488). This new laser enables high-resolution spectroscopy and nonlinear X-ray studies for more precise investigations into ultrafast processes and chemical reactions.