16 August 1996
Vol 273, Issue 5277

About The Cover

Light emission revealing the propagation and composition of carbon plasmas generated by ablation of a graphite target in vacuum with a pulsed argon-fluorine laser, at times from 100 nanoseconds (upper left) to 1500 nanoseconds (lower right) after the laser pulse. Three principal plasma regions were discovered and related to the quality of amorphous diamond-like carbon films. See page 898 and the special section on Thin Films beginning on page 878. [Image: D. B. Geohegan and A. A. Puretzky]