Abstract

Laser alignment instruments usually operate by using the laser beam itself, i.e., the locus of its energy center, as the axis of the collimating and measuring base line. However, the locus of the laser beam energy center is not a steady-state straight line; it follows any variation in the laser output and thus can drift. This has a direct influence on the precision of the collimation measurement. The new type of laser aligner we introduce here, however, uses the axis of an annular interference pattern as a base; this pattern has a high degree of stability both in space and time, so that it is essentially unaffected by the drift of the laser beam (including its translation and angular displacement).

© 1987 Optical Society of America