Study of High Efficiency Phase-Only Diffractive Optical Elements

Doktorsavhandling, 1992

This work deals with the design, simulation, manufacture, and evaluation of diffractive optical elements. Particularly, kinoforms and diffractive bifocal intraocular lenses are studied. Evaluation of kinoforms, i.e. computer generated phase holograms, manufactured by photolithography and electron-beam lithography are presented. E-beam lithography has the ability to manufacture high efficiency diffractive optical elements, in particular micro-Fresnel lenses, which was not possible before. Multilevel resist kinoforms manufactured with direct writing e-beam lithography with a diffraction efficiency up to 85% are presented. How to compensate for the electron scattering during exposure and to optimize the development are discussed in two different papers within this thesis. Kinoforms used as array illuminators and/or for use in laser machining are/is also presented. The thesis also treats the optical properties of diffractive bifocal intraocular lenses by using three methods: bench measurements, computer simulations, and in vivo measurements. The last part of the thesis deals with letter imaging with diffractive bifocal intraocular lenses using computer simulations.