A simple and very compact apparatus is described for obtaining the absolute efficiencies of a wide assortment of grating types and sizes. The device allows a grating to be measured in the configuration it will actually be used in, which can be particularly valuable in cases where the grating efficiency may vary significantly with the method in which it is used. Some results are given for a number of gratings.
R. L. Hilliard,
"Versatile Method For Measuring Absolute Grating Efficiencies", Proc. SPIE 0196, Measurements of Optical Radiations, (15 November 1979); doi: 10.1117/12.957971; https://doi.org/10.1117/12.957971