Narrow Bandwidth, Tunable, Holographic Filters for Solar Atmospheric Studies

Narrow bandwidth filters using holographic reflection gratings will be developed for application in solar atmospheric studies, where rapid wavelength tunability over about a 1 A range is required. A holographic grating filter for monochromatic imaging at the Ha line has already been demonstrated by Accuwave Corporation, with 0.12 A bandwidth (FWHM) and -30 dB sidelobe levels at l.1 A from the peak. Techniques for improving this basic filter by incorporating rapid wavelength tunability, materials for holographic filters at wavelengths shorter than Ha such as the CaII line, and improvements in optical throughput, resolution, and field of view will be investigated.