초록 ▼

The optical path lengths of a plurality of comparison laser beams directed to impinge upon a common target from different directions are compared to that of a master laser beam by using an optical heterodyne interferometric detection technique. The technique consists of frequency shifting the master

The optical path lengths of a plurality of comparison laser beams directed to impinge upon a common target from different directions are compared to that of a master laser beam by using an optical heterodyne interferometric detection technique. The technique consists of frequency shifting the master laser beam and combining the master beam with a first one of the comparison laser beams to produce a time-varying heterodyne interference pattern which is detected by a photo-detector to produce an AC electrical signal indicative of the difference in the optical path lengths of the two beams which were combined. The optical path length of this first comparison laser beam is adjusted to compensate for the detected difference in the optical path lengths of the two beams. The optical path lengths of all of the comparison laser beams are made equal to the optical path length of the master laser beam by repeating the optical path length adjustment process for each of the comparison laser beams. In this manner, the comparison laser beams are synchronized or timed to arrive at the target within ±1×10-12 second of each other.

대표청구항 ▼

A method for timing a comparison beam and a master beam of partially coherent electromagnetic radiation of the same frequency and finite bandwidth comprising: shifting the frequency of the master beam relative to that of the comparison beam; combining the two beams to produce an optical heterodyne i

A method for timing a comparison beam and a master beam of partially coherent electromagnetic radiation of the same frequency and finite bandwidth comprising: shifting the frequency of the master beam relative to that of the comparison beam; combining the two beams to produce an optical heterodyne interference pattern which is indicative of the difference in optical path lengths of the beams; detecting the interference pattern of the combined beams; and adjusting the optical path length of the comparison beam until the interference pattern indicates that the difference in optical path lengths of the beams is zero.