When a lens and its focal length are extremely small, all aberrations scale with the size of the lens and at some point become ignorable. For highest resolution, it is desirable to have a deep ultraviolet and high numerical aperture lens. Conventional lens making methods have proved inadequate for providing diffraction limited deep UV lenses which are reproducible enough to be used in metrology applications in the semiconductor industry, for example. Microlenses as described in this project have the following advantages: extremely reproducible; deep ultraviolet and large numerical apertures are possible; they have no polished curved surfaces; they are potentially diffraction limited; and they are relatively broadband although they are made from only one type of glass (fused silica, UV grade, for example). Applications include semiconductor metrology, inspection, and lithography; general ultraviolet and fluorescence microscopy; endoscope technology for non-invasive surgery or viewing; optical memory readers and writers; fiberoptic coupling; and laser diode collimation.The potential commercial application as described by the awardee: Applications of the research include semiconductor inspection, metrology, lithography, and pattern alignment; general ultraviolet microscopy; general fluorescence microscopy; endoscopes; fiberoptic coupling; laser diode collimation; and optical memory read/write systems.