The invention relates to a location beam expanding
system for
ultraviolet laser, comprising a first lens and a second lens arranged in the
light beam incidence direction; wherein the first lens is a crescent-shaped negative lens with back side thereof bent towards the incidence direction of light
ray, the second lens is a plano-convex positive lens; the beam expanding
system composed of the first lens and the second lens can expand
diameter of incidence
laser beam by 12 times and still eject the
laser beam in the form of parallel light. As far as the beam expanding
system of the invention is concerned, as the negative lens is short in
focal length, thus not affecting aberration much; however, the positive lens is the main part which determines quality of outgoing beam from a
beam expander. The beam expanding system enjoys a 12 times of beam expanding
magnification, therefore a positive lens is enough to ensure quality of expanded outgoing beam; on the basis, not only shaping requirements are met, but also the best
imaging quality is achieved; in addition, contour dimension is guaranteed to be the minimum, the
imaging quality of the beam expanding system is very ideally balanced and volume of the whole lens is very small.