Simulation of diffraction gratings in the fresnel diffraction regime: Using the ab-initio iterative fresnel integrals method

Computer-based virtual experiments and simulations in all branches of physical sciences and engineering has attracted wide spread interest among the researchers from all parts of the scientific world due to its multifaceted applications and versatility. Computer simulation of diffraction phenomena, including simulation of diffraction gratings, has widespread applications, since diffraction gratings, especially amplitude diffraction gratings, are used extensively in spectrographs and spectrometers. Usually, these are used in the Fraunhofer (far-field) regime. In this Chapter, we have used the ab-initio Iterative Fresnel Integral Method (IFIM) for the complete simulation of the near-field Fresnel diffraction images from any amplitude diffraction grating. The simulations can be performed in any PC in a reasonable amount of timeand are executed in the MATLAB language. Complete explanations of the computational method, as applied to the diffraction gratings, are described, along with the simulation algorithms. Comparison of the simulated results with certain situations, which can be described by analytical equations, is made. The agreement confirms the correctness of the present simulation methods that will pave the way for future studies. We finally mention some extensions of the N-stilt problem, namely the application to tilted and rotating gratings and multi-wavelength illuminations.