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docs:become [2020/04/22 22:56] pklapetek |
docs:become [2020/04/22 23:01] pklapetek |
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| - | The transition from transition geometry to reflection geometry was done first with perfect electric conductor as a grating material. The same motive as in the Become grating is used and also | + | The transition from transmission geometry to **reflection grating** geometry was done first with **perfect electric conductor** as a grating material. The same motive as in the Become grating is used and also |
| the same voxel spacing (5 nm), it is only from a different materials for calculation speed and simplicity. All the computational details were same as in the previous example. | the same voxel spacing (5 nm), it is only from a different materials for calculation speed and simplicity. All the computational details were same as in the previous example. | ||
| To get the data normalization to the incident wave intensity we used perfect electric conductor plane only (no grating motives) and evaluated the electric field intensity in | To get the data normalization to the incident wave intensity we used perfect electric conductor plane only (no grating motives) and evaluated the electric field intensity in | ||
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| even if they are not infinitely periodic. | even if they are not infinitely periodic. | ||
| A bigger problem is that the diffracted intensity is about 0.147 of the incident intensity, | A bigger problem is that the diffracted intensity is about 0.147 of the incident intensity, | ||
| - | which is less than expected (the expected value is 0.178). Something has to be wrong. | + | which is less than expected (the expected value is 0.186). Something has to be wrong. |
| The first suspect is the refractive index. | The first suspect is the refractive index. | ||
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| Another suspect is the voxel spacing. In the first tests for 5 nm and 10 nm voxel spacing the resulting diffraction maximum was nearly same when studied on PEC (less than 0.5 percent difference). In past we have however observed that the voxel spacing has an impact on the reflectance on real metals (not on PEC, which is ideal). | Another suspect is the voxel spacing. In the first tests for 5 nm and 10 nm voxel spacing the resulting diffraction maximum was nearly same when studied on PEC (less than 0.5 percent difference). In past we have however observed that the voxel spacing has an impact on the reflectance on real metals (not on PEC, which is ideal). | ||
| Too coarse mesh cannot treat the metal correctly, probably due to its small skin depth. | Too coarse mesh cannot treat the metal correctly, probably due to its small skin depth. | ||
| - | Here, in a quick check, for the fitted model we get reflectances of 0.959 for 10 nm voxel size, 0.962 for 5 nm voxel size and 0.958 for 2 nm voxel size, when roughly evaluated from the local fields. This means differences up to 1 percent. However, the difference between the expected value and the simulated value is about 15 percent. So, reflectance itself is probably also not the source of troubles. | + | Here, in a quick check, for the fitted model we get reflectances of 0.959 for 10 nm voxel size, 0.962 for 5 nm voxel size and 0.958 for 2 nm voxel size, when roughly evaluated from the local fields. This means differences up to 1 percent. However, the difference between the expected value and the simulated value is about 20 percent. So, reflectance itself is probably also not the source of troubles. |
| The voxel size could impact the overall performance in more general way than only to wrong | The voxel size could impact the overall performance in more general way than only to wrong | ||
docs/become.txt ยท Last modified: 2020/04/24 12:27 by pklapetek
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