Beam projecting device

摘要

A beam projecting apparatus includes a light source that emits a laser beam and a colliminating lens that renders the emitted laser beam a substantially parallel beam. A beam projecting device includes a beam projecting portion from which the laser beam is projected outwardly so that the laser beam has a beam waist located at a predetermined position spaced from the beam projecting apparatus. The beam projecting apparatus further includes a system that detects a curvature of wavefront of the substantially parallel beam at the predetermined position.