Isolated flashes of extreme ultraviolet light can now be squeezed into a spot smaller than a single bacterium.
Attosecond light pulses usually spread out too much to trigger the complex reactions needed for next-generation electronics. A specialized focusing setup squeezed these pulses down to a 0.4 micron spot, hitting a peak intensity of 3 quadrillion watts per square centimeter. Traditional physics assumed extreme ultraviolet light was too difficult to control for high-speed nonlinear optics. By breaking that barrier, engineers can now manipulate electrons inside solid materials at speeds a billion times faster than current computer chips. This opens the door to processing data at frequencies that were once considered physically impossible.
Submicrometer focusing of isolated attosecond XUV pulses approaching 10$^{16}$ W/cm$^2$
arXiv · 2604.25485
We demonstrate submicrometer focusing of isolated attosecond pulses (IAPs) in the extreme ultraviolet (XUV) region using a custom ellipsoidal mirror. The obtained focal spot sizes were verified using knife-edge measurements with a sharp silicon edge, confirming reproducible dimensions down to 0.46 $\mu$m $\times$ 0.36 $\mu$m (FWHM), approaching the diffraction limit. Focusing a 1.1-GW tabletop IAP source yields a peak intensity of 3 $\times$ 10$^{15}$ W/cm$^2$, and a realistic pathway toward 10$