Replica grating study

Methods are outlined which were used to test the response of replica diffraction gratings to a space environment, specifically the response of the replica gratings to thermal-vacuum and electron irradiation stress. It is concluded that there probably is some degradation to thermal stress, but that there is probably no significant degradation due to a vacuum environment. It is further concluded that the degradation of performance of replica gratings because of electron irradiation is due to the interaction of the electrons and the replica grating substrate and not to the replication material itself. Replica and original gratings on the same substrate material should thus respond to particle irradiation in the same manner. A study is presented on the variation of refraction index of a space-related material, Nd:CaF2, with wavelength, percent neodymium doping, and temperature.