LASER-ELIMINATION OF MODE BEATING

摘要

A laser system designed to minimise mode beating by splitting an incident laser beam into two approximately equal components, transmitting the components along separate paths of unequal lengths and recombining the components at a beam combiner to form the emergent laser beam. The elimination of laser mode beating is effected at frequencies dependent upon the interferometric path difference. Mode beating elimination at further frequencies is possible using further splitter/combiner combinations in series. A laser system comprises a laser beam source and an optical beat suppression system, or such systems in series, thus providing a low inherent noise source as drive to a line and field scanner of an object surface or developed film, or by the inclusion of a modulator, to provide a source to a similar scanner of a display screen or film recorder. A three-colour laser projection display system includes two laser beam sources with beat suppression optics and uses conventional means of colour separation/modulation/recombination to provide the drive to a scanner for a display screen.