For reflective dividing of a laser beam and focusing in two spots with a fixed distance between, a Fresnel biprism is used. When there is a need for a more frequent change of distance between the spots, a new solution is proposed.
© 1990 Optical Society of America
Illija Belic, "Device for reflective dividing of a laser beam with adjustable distance between the two focus spots," Appl. Opt. 29, 3876-3876 (1990)