A kinoform lens and its substrate are usually treated as two distinct
components with a common interface. Thick kinoform lenses treat the re
lief profile and the substrate as an integrated component. An analytic
al approach for the design of higher-order thick kinoform lenses for s
tigmatic imaging between extra-axial conjugate points is presented. An
illustrative example is given. (C) 1997 Optical Society of America.