Correlation between Efficiency of Diffraction Gratings and Theoretical Calculations over a Wide Range

Abstract

Results described here show that infinite conductivity theory matches experimental grating efficiencies very closely when wavelengths exceed 4 µm, in fact often serves adequately above 1 µm. At shorter wavelengths, i.e. the visible region, the influence of finite conductivity on the theory must be included, in which case once again excellent agreement with experiment can be demonstrated. The nature of anomalies, especially as affected by different metal surfaces, is a highly sensitive test for theory. In the vacuum ultraviolet region correspondence between theory and experiment could still be observed, although some new practical limitations intervene.