A team of scientists at Technische Universität Wien in Austria, Max Planck Institut für Quantenoptik in Garching, Germany, and Universität Würzburg in Germany has reported the generation of coherent 1.77-nm x-rays. Reported in the April 23 issue of Physical Review Letters, the achievement promises to enable the development of compact x-ray sources for use in biology and biochemistry.

In the experiments, the researchers exposed a helium gas jet to 2.5-mJ pulses of 780-nm radiation from a Ti:sapphire laser. The 10-fs-long pulses ionized the helium, generating soft x-rays with photon energies of up to 700 eV. The setup yielded 20,000 1.77-nm photons per second.