Analysis of the effect of refractive index of medium on the diffraction efficiency of the reflecting and phase-relief diffraction gratings

Numerical computations are used to study the effect of the refractive index of medium (gas or liquid) on the diffraction efficiency of the relief diffraction gratings. The effect of the grating material on the dependence of the diffraction efficiency on the refractive index of the medium is studied for the transmitted diffraction. A one-to-one dependence of the diffraction efficiency on the refractive index of the medium is obtained for both transmitted and reflected light. The effect can be used in compact diffractometers for the study of the refractive indices of liquids.