Production and control of refractive and diffractive microlenses

The authors discuss two examples of microlenses where the generation process and the interferometric control are strongly interwoven. For refractive lenses they use lenses melted in photoresist and also reactive ion etched samples. The control is done with the help of a phase shifting interference microscope of the Mach-Zehnder type. An evaluation software was developed under windows. The other type of lenses are HOE-lenses in dichromated gelatin. With the help of a ray trace program the authors are able to compute a computer generated hologram (CGH) which can be used to aspherize the illuminating wavefronts during exposure. This CGH is written with the help of a laser beam pattern generator having mu m-accuracy and resolution. The amplitude structure may be transferred into a phase structure by reactive ion etching. In this way a highly efficient CGH can be produced for the precompensation of spherical wavefronts.<
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