| abstract |
In one embodiment, a refractive-diffractive hybrid telescope 40 having a refracting convex-concave lens 42, a hybrid refractive-diffractive optical element 48 with at least one diffractive surface 52, and a bi-convex lens 24 is provided. In another embodiment, a refractive-diffractive hybrid telescope 80 is disclosed as having a two-lens converter 92 in combination with the binary telescope 40. The two-lens converter 92 has a refracting convex-concave lens 82 and a concave-convex lens 88. The diffracting surface 52 of the hybrid refractive-diffractive optical element 48 preferably has kinoform profiles 112a-d, 112a'-d' or approximated kinoform profiles 122a-d, 122a'-d', 132a-d, and 132a'-d'. Also disclosed is a method for reducing aberration in an optical system. The benefits associated with the present invention include the following: (1) the Abbe number of an optical component employing refractive and diffractive optical elements can be adjusted to a desired value; and (2) hybrid telescopes of the present invention 40 and 80 help simplify telephoto systems and provide comparable or better image quality when compared with conventional refractive telescopes. |