FOCUSSED LASER BEAM OPTICAL SYSTEM

摘要

The focal range of a focussed laser beam is enlarged with a simple optical stop where the beam has a gaussian cross-sectional profile. The stop is arranged between the laser producing the beam, and a beam focussing lens system, and it is provided with an aperture of predetermined diameter with respect to that of the laser beam whereby the outer portion of the beam represented by the low intensity skirts of the profile curve is stopped. This arrangement can influence the focal range up to a 75 per cent increase over that obtained with the unstopped beam.