08/04/2006
Interdisciplinary Team Demonstrates New Technique for Manipulation of "Light Beams"
Robert Tindol
It may be surprising that a laser beam, when shot to the moon and returned by one of the mirrors the Apollo astronauts left behind, is a couple of miles in diameter at the end of its half-million-mile round trip. This spread is mostly due to atmospheric distortions, but it nonetheless underscores the problems posed to those who wish to keep laser beams from diverging or focusing to a point as light travels through a medium.