01 May 2015
Vol 348, Issue 6234

About The Cover

Cover image expansion

COVER Sculpting coherent x-ray light with visible lasers. When an atom is hit by a strong rosette-shaped laser field (purple) (a superposition of red and blue circularly polarized lasers with opposite helicity), an electron (green) is ripped from, and recollides with, the parent ion. The result is the emission of bright, circularly polarized light at extreme ultraviolet wavelengths (blue). For more on cutting-edge advances in light and optics, see page 514.
Image: The Kapteyn/Murnane Group and Steve Burrows, JILA; and the Cohen Group, Technion