Nanoscale freestanding gratings for ultraviolet blocking filters

Ultraviolet (UV) blocking filters are needed for atomic flux imaging in environments where high levels of ultraviolet radiation are present. Freestanding gratings are a promising candidate for UV filtering. They have a high aspect ratio (similar to 13), narrow (similar to 40 nm) slots, and effectively block UV radiation. The grating fabrication process makes use of several etching, electroplating, and lithographic steps and includes an optional step to plug pinholes induced by particles during processing. Gratings were-successfully manufactured and tested. Measured UV transmissions of similar to 10(-5) and particle transmissions of similar to 10% are in agreement with theoretical predictions. (C) 1998 American Vacuum Society. [S0734-211X(98)03806-2].