An aiming system for use in a small height scan engine chassis. The aiming system includes a beam source assembly generating an input beam along a central axis and a collimator assembly having a lens group that defines a tilt axis having a tilt angle, α, relative to the central axis, to deflect the input beam from the central axis onto the tilt axis. The collimator assembly further includes a recess within which a diffractive optical element is sealably mounted to convert the deflected input beam into an aiming pattern at a focal distance of the lens group.