Special Optics' in-line beam steerers are convenient devices that precisely change the angle or alignment of optical beams. Unlike Risley prisms, in-line beam steerers move a beam in a cartesian coordinate system rather than in a polar coordinate system. With a single adjustment, they deflect the beams horizontally or vertically, making them much easier to use, compared with the typical two-mirror setup.The in-line beam steerer is an adjustable wedge formed by a planoconcave and a planoconvex lens that are joined using a thin layer of index-matching fluid. Displacement of one lens with respect to the other changes the wedge angle experienced by the beam, thereby steering it.The devices also have a smaller footprint than typical two-mirror alignment systems. They feature 6-, 10- or 15-mm clear apertures, zero beam displacement, greater than 98% transmission and broadband optical coatings. Special Optics has manufactured optical components and optical systems for medical, military, industrial and semiconductor applications since 1965. Custom designs, materials and deflection ranges are available.