| Autor: |
M. Heissmeier, Pekka Savander, Martin Schrader, Walter P. Hofmann, Stefan Haselbeck, Norbert Streibl, Johannes Schwider, Ulrich Krackhardt, Bernd Manzke, Martin Sperl |
| Rok vydání: |
1993 |
| Předmět: |
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| Zdroj: |
SPIE Proceedings. |
| ISSN: |
0277-786X |
| Popis: |
Computer generated holograms (CGH) consist of patterns which have been calculated numerically starting from the desired function of the optical component and the known physical laws of diffraction. The real fabrication of such holograms poses two different tasks. First the computed pattern has to be converted into one mask or a set of masks. Thereby submicron resolution is required for CGHs that are to be used for visible light. This means that one has to use microlithographic techniques such as electron-beam or laser lithography. The second task is to achieve the necessary groove depth and profile. Wet etching techniques have been quite common for this purpose but they have two disadvantages: it is difficult to obtain a precise etch stop particularly with very fine structures due to capillary effects and mostly one is constrained to certain crystallographic orientations. This makes it hardly possible to achieve directional anisotropic etching in glass. Dry etching techniques overcome both of these problems. The foundry for micro-optical elements in Erlangen makes use of laser lithography and reactive-ion etching. Both technologies are discussed in some detail. The scope of computer generated holograms ranges from the well known Dammann-gratings, gratings which produce arrays of light spots of equal intensity, to very complex two- dimensional structures for example for the correction of aberrations or for three-dimensional displays. In his paper we also describe some results with the production of microlenses that can be realized using our technologies.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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