This Small Business Innovation Research Phase II project will demonstrate and test a compact, low cost and ultra-narrow bandwidth ( 0.3A) prototype holographic grating filter system for solar observing at the UV Ca K line (3933A). This technique developed during Phase I addresses a key requirement for narrow bandwidth filters in the UV wavelength because of the difficulties in fabricating Lyot and similar interference filters with sufficient spectral resolution and optical quality. During Phase II, suitable recording materials will be optimized and used to record volume gratings using holography techniques developed during Phase I. The prototype filter system will be tested at Big Bear Solar Observatory or other suitable test sites. This Phase II program will enable sub-Angstrom passband filters to be constructed for field testing and provide further technical improvement for commercialization of this new technology. Potential commercial applications of this new technology include optic receivers for optical remote sensing; pollutant, chemical, metal and mineral detection; solar-blind filters for free-space optical communications; high density optical disks and holographic data storage; and UV optical projection lithography.