Self‐Induced Transparency Found in Sulfur Hexafluoride

By applying a short, intense pulse from a Q‐switched carbon dioxide laser to gaseous sulfur hexafluoride, Kumar Patel and Richard Slusher of Bell Telephone Laboratories have made the gas transparent to 10.6‐micron radiation (Phys. Rev. Letters 19, 1019, 1967). They have thus verified the self‐induced transparency first found with a ruby laser system by Erwin Hahn and Samuel McCall of Berkeley (PHYSICS TODAY, August 1967, page 47). To observe the effect, one must match the exciting frequency to a strongly absorbing transition in the sample.