title: Ultraviolet groove efficiency of a holographic grating: implications for a dual-order spectrograph.
abstract: The ultraviolet groove efficiency for a holographically ruled diffraction grating with a trapezoidal profile has been measured. The efficiencies for the +/-1 and the zero orders are in good agreement with those derived from scalar theory. The +/-1 orders have equal efficiency as a function of wavelength. The peak of the sum of fitted groove efficiency functions is 76%, a level that is competitive with the groove efficiency of a mechanically blazed grating. We suggest that a normal-incidence grating mount with detectors at both orders will offer a system with twice the efficiency and provide a built-in redundancy. We discuss design considerations for reducing astigmatism equally in both orders in such dual-order mountings.
authors: Department of Physics and Astronomy, the Johns Hopkins University, Baltimore, Maryland 21218, USA. stephan@pha.jhu.edu
authors: S R
authors: SR
authors: McCandliss
authors: E B
authors: EB
authors: Burgh
authors: P D
authors: PD
authors: Feldman