A kinoform is a type of computer-generated converging lens that is able to efficiently focus light to a point.
[1] They typically use holography to reproduce the optical phase profile of a normal converging lens, albeit on a flat surface.
[2] They can be used in areas such as focusing x-ray radiation, or in the study of nanomaterials.
Diamond is often used in kinoform lenses as it has a high thermal conductivity.
[3] Higher chromatic aberration is a common drawback.