Relation between angles of diffraction and diffraction efficiency of diffractive elements

The authors have attempted to provide some information on diffractive optics between the resonance and the paraxial domain. Two simple considerations, which are based on specific assumptions, have been described. In the first gedanken experiment it was shown that it is only possible to obtain a diffraction efficiency near 100% in the resonance domain, i.e. if α≈90°. The assumption was: with a dielectric grating it is impossible to obtain a grating transmittance with an amplitude modulation on a scale which is significantly larger than the wavelength. In the second discussion the authors tried under some assumptions to get a first idea of the characteristic dependence of η on the angle of diffraction. The presented experiment was in agreement with prediction