Two‐Photon Fluorescence Detects Ultrashort Pulses

Light pulses shorter than picoseconds can now be directly displayed and measured, according to a group of Bell Telephone Laboratories scientists. Several techniques for generation and measurement of ultrashort, intense light pulses have been known for a number of months. But until now, the resolution limit of pulse‐duration measurements has been about $10−13 sec.$ Joseph A. Giordmaine described for PHYSICS TODAY a technique that he, Peter M. Rentzepis, Stanley L. Shapiro and Kenneth W. Wecht have developed, which extends this resolution, they believe, below $10−14 sec.$