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app:topography_grating
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app:topography_grating [2018/01/30 15:09] pklapetek |
app:topography_grating [2018/08/31 08:41] (current) pklapetek |
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| To help with establishing the parameter file and volume material and post-processing we have created a simple Gwyddion module (so we can easily pick the requested height field and easily show results), however both data preparation and postprocessing could be done using any other tool, none of specific Gwyddion algorithms was used. | To help with establishing the parameter file and volume material and post-processing we have created a simple Gwyddion module (so we can easily pick the requested height field and easily show results), however both data preparation and postprocessing could be done using any other tool, none of specific Gwyddion algorithms was used. | ||
| - | Note that the example was created using GSvit 1.2, some of its limitations may be overcome in later versions, making the simulation more straightforward. | + | {{ :app:b_grating_gratingmodel.png?200|}} |
| Image on the right shows a scheme of the computational volume used for the simulation (a cross-section). We use a parallelepiped of 230x230x200 voxels bounded by simple absorbing boundary conditions. A plane wave source is established using Total/Scattered field (TSF) approach, but only single plane is used to excite the plane wave (all the other faces are skipped). This is due to periodic boundary conditions that are applied, forming four internal computational domain walls parallel to light propagation direction. Only internal 200x200x200 voxels are therefore used for further computation as shown on the right image. A height field representing the grating is centered in the parallelepiped. Linear material is used to introduce height field, i.e. values of electric and magnetic properties are loaded for full volume (an alternative would be to load Gwyddion height field using vector material approach, or to construct totally synthetic vector data input based on primitive geometric entities). | Image on the right shows a scheme of the computational volume used for the simulation (a cross-section). We use a parallelepiped of 230x230x200 voxels bounded by simple absorbing boundary conditions. A plane wave source is established using Total/Scattered field (TSF) approach, but only single plane is used to excite the plane wave (all the other faces are skipped). This is due to periodic boundary conditions that are applied, forming four internal computational domain walls parallel to light propagation direction. Only internal 200x200x200 voxels are therefore used for further computation as shown on the right image. A height field representing the grating is centered in the parallelepiped. Linear material is used to introduce height field, i.e. values of electric and magnetic properties are loaded for full volume (an alternative would be to load Gwyddion height field using vector material approach, or to construct totally synthetic vector data input based on primitive geometric entities). | ||
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| A typical snapshot from the simulation is shown in the following image (on the left). As a result we obtain a far field radiation pattern as shown in the right image (shown for two different grating depths). | A typical snapshot from the simulation is shown in the following image (on the left). As a result we obtain a far field radiation pattern as shown in the right image (shown for two different grating depths). | ||
| + | |||
| + | ---- | ||
| + | // | ||
| + | {{ :app:img_topography_grating.png?120|}} | ||
| + | Sample parameter file: {{app:topography_grating.tar.gz|grating from topography}}. | ||
| + | \\ | ||
| + | A simulation of a reflection grating based on a real topography provided as a height field. The resulting 1D diffraction pattern is a graph in the output Gwyddion file. | ||
| + | // | ||
| + | ---- | ||
app/topography_grating.1517321352.txt.gz · Last modified: 2018/01/30 15:09 by pklapetek
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