A spatial mechanism for pilot laser alignment with four independently controlled degrees of freedom

Alignment mechanism for optical components, such as mirrors for manipulating laser beams, frequently require four degrees of freedom: two translations and two rotations, i.e. a four axis system. When the adjustment of one axis influences the others, as often will be the case, alignment procedures can be rather cumbersome. The mechanism, described in this paper, has four mutually independent adjustments, each controlling just one axis. Rotation takes place around a fixed point, which can be located freely in space. A computer simulation program has been developed to determine first and higher order deviations. This program proved to be a useful designer's tool to optimize the construction with respect to other system parameters.