Rigorous analysis of 3D gratings by the Fourier Modal Method
3D gratings are modulated along the x-, y-, and z-direction and are periodic in x- and y-direction. VirtualLab™ 4.9 and higher enables the rigorous analysis of 3D surface gratings, holographic gratings, artificial media, zeroth order gratings, antireflection gratings and photonic crystals with features from nanometer to micrometer scale. Various customization features allow the analysis and optimization of gratings with user defined structures. The powerful stack concept allows to describe gratings as a sequence of surfaces and homogeneous as well as inhomogeneous media. In addition the programmable interface and the programmable medium enable the description of structures by formulas.
Your Benefit
- Simulation of sub-wavelength gratings, i. e. zeroth order gratings, artificial media, moth-eye structures and polarizers with the rigorous Fourier Modal Method.
- Simulation of high NA beam splitting gratings.
- Analysis of the near field including polarization effects.
- Investigation of tolerances and optimization by the parameter run.
Selected Features
Fourier Modal Method for three-dimensional gratings. The Fourier Modal Method is used in VirtualLab™ to analyze the light propagation through 3D periodic structures. It allows to adjust numerical parameters to find the best compromise between accuracy and calculation speed. Moreover it gives insight into the convergence of the technique.
Analyzers to calculate efficiencies, near field and Rayleigh coefficients of the distinct diffraction orders. The VirtualLab™ Grating Efficiency Analyzer allows you to calculate efficiencies, near field, polarization, all electric and magnetic field components as well as Rayleigh coefficients of the distinct diffraction orders. Furthermore you can calculate the overall reflectance, transmittance, and absorption.
Sub-wavelength gratings for antireflection structures. Sub-wavelength 3D gratings are often used as reflection or antireflection structures replacing coatings. Moth-eye antireflection structures are a well known example. Pillars, cones and pyramids are further typical surface structures of practical interest.
Modeling of gratings with customized height profiles or index modulations. VirtualLab™ supports the import of measurement data of grating profiles. Furthermore programmable interface and programmable medium enable the definition of customized height profiles and index modulations by formulas. The snippets Snippet_015 and Snippet_016 demonstrate for example the introduction of cone-type and pyramid-type surface gratings. The stack concept enables the description of gratings as a sequence of surfaces as well as homogeneous and inhomogeneous media.
Parameter Run to vary parameters of the incident wave as well as structural and numerical parameters of the grating in a convenient way. The powerful parameter run of VirtualLab™ enables the investigation of the effect of tolerances and the optimization of grating structures. A single parameter variation, a multidimensional scanning parameter variation and a random (Monte-Carlo) parameter variation can be done.
Sketch of pillar-type grating showing free parameters available within parameter run.