Advancing the Manufacturing of High Precision Optics by Replication in Different Substrate Materials

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9632929 Lee Two new replication techniques will be developed to reduce the costs of manufacturing precision diffractive gratings and optics, binary optics, micro-optics and computer generated holograms. These replication techniques will show their advantages specially when they are non centro-symmetric, their aperture areas are not circular (e.g. square or hexagonal), and/or they are in an array format with precise center-to center spacings. The first technique can be applied to replicate infrared as well as visible-uv precision optics on environmentally durable substrates. It requires first generating a gray level mask with only one writing step of an electron beam by controlling the electron dosage spatially. Then, using this gray level mask, it requires for each copy only one iteration of exposing the analog photoresist and transferring the analog photoresist pattern into the substrate by chemically assisted ion beam etching (CAIBE). Since multiple substrates can be etched simultaneously, the CAIBE is a batch process and the etching cost for each copy is reduced. Moreover, since the same gray level mask can be used over and over again for making many copies with a projection aligner, the cost of generating the gray level mask will be spread over the number of copies. The copies of diffractive optics can be in different (infrared-uv) substrate materials. The second replication technique starts with a master on quartz or glass. Replica are made from liquid photopolymer by molding. Diffractive optics on curved surfaces or with integrated receptacles can be replicated with liquid photopolymer to work in the visible range. Being able to put diffractive optics on curved surfaces allows the optical designers additional degrees of freedom for aberration removal; being able to replicate diffractive optics with integrated receptacles reduces the assembly costs. In other words, our overall technical objectives will be demonstrating the feasibility of these two replication techniques in different mater ials as well as studying the manufacturing issues. Several industrial collaborators have shown strong interests in the proposed investigations. The overall effort will be divided approximately as follows: 70% to the first replication technique and 30% to the second.