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| Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
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docs:become [2020/03/29 12:14] pklapetek |
docs:become [2020/04/02 12:03] pklapetek |
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| in all the other calculations. | in all the other calculations. | ||
| - | The image below shows the normalized angular dependence of the diffraction from the grating. | + | The image below shows the normalized angular dependence of the diffraction from the (finite size) grating. |
| {{:docs:become_grating_2d_normalised.png?600|}} | {{:docs:become_grating_2d_normalised.png?600|}} | ||
| - | It can be seen that there is a slight asymmetry in the result which needs to be analyzed, probably due to wrong placement of far-field points. The average intensity of the s+1 and s-1 diffraction orders is 0.183 of the incident intensity. | + | When inspected in detail, it can be seen that there is a slight asymmetry in the result which needs to be analyzed, probably due to wrong placement of far-field points. The average intensity of the s+1 and s-1 diffraction orders is 0.178 of the incident intensity for the default silver model (not the Become one). |
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| + | As we use the PLRC metal handling we can not enter the refractive index directly to the calculation. Instead we need to use some dispersive model, in our case based on two critical points. We have fitted part of the optical database data by the model to get closer to the prescribed values, however there are still small differences (unless we restrict the fitting spectral region much more, which would lead to quite unrealistic dispersive model). The correspondence of the fitted refractive index and database data is shown below. | ||
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| + | {{:docs:becomefit.png?600|}} | ||
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| + | To compare its impact on results, here is a list of different metal model settings and results: | ||
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| + | * metal setting: 6 1.03583 0 1.37537e+16 1.25733e+14 2.1735 -0.504659 7.60514e+15 4.28131e+15 0.554478 -1.48944 6.13809e+15 6.62262e+14 means n=(0.129 + 3.87i) and leads to first order diffraction of 0.172 | ||
| + | * default metal setting: 6 0.89583 0 13.8737e15 0.0207332e15 1.3735 -0.504659 7.59914e15 4.28431e15 0.304478 -1.48944 6.15009e15 0.659262e15 means n=(0.036 + 4.147i) and leads to first order diffraction of 0.178 | ||
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| + | Dependence on problem size: | ||
| ===== 3D calculation ===== | ===== 3D calculation ===== | ||
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| The aspects that need further investigation or tuning: | The aspects that need further investigation or tuning: | ||
| - | * polarisation correctness (TE mode is p-polarisation) | ||
| * far-field calculation postprocessing speedup, now very slow, printing many debugging data. | * far-field calculation postprocessing speedup, now very slow, printing many debugging data. | ||
| - | * cross-check metal refractive index (now relying on pre-fitted database data) | + | * cross-check metal refractive index (now relying on pre-fitted database data, which is wrong) |
| - | * correct placement of far field points (get rid of the slight asymmetry observed) | + | * there is still slight asymmetry |
| * evaluate the voxel size vs. speed vs. accuracy for the benchmark. | * evaluate the voxel size vs. speed vs. accuracy for the benchmark. | ||
docs/become.txt · Last modified: 2020/04/24 12:27 by pklapetek
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