Researchers at Skoltech, together with a colleague from the Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences, working within the joint SIOM–Skoltech laboratory, have determined how to select the thickness and density of a plasma target so that a pulse passing through it retains its attosecond duration and high intensity. The results will help improve the design of plasma-based sources of ultraviolet and X-ray radiation used to study ultrafast processes in matter.

The work is published in Applied Physics Letters.

An attosecond is 10⁻¹⁸ of a second. Pulses of this duration can be compared to an ultrafast camera flash: They make it possible to effectively “freeze” the motion of electrons and investigate processes that cannot be resolved using longer pulses. This is important for studying atoms, molecules, solids and new materials.