User Tools
app:ters
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision | |||
|
app:ters [2018/02/02 09:45] pklapetek |
app:ters [2018/02/02 10:32] pklapetek |
||
|---|---|---|---|
| Line 7: | Line 7: | ||
| The second remarkeable effects is the antenna effect. When we prepare a structure with size that is comparable to the wavelength of the illuminating light, we form an antenna similarily like e.g. in radio communications. This leads to significant local enhancement of the electromagnetic field around the antenna due to resonance effects. Here we meet the enhancement, which is so important for TERS probes. An example of the antenna effect is shown in discussion of [[app:nanoantenna|Plasmonic nanoantenna]]. | The second remarkeable effects is the antenna effect. When we prepare a structure with size that is comparable to the wavelength of the illuminating light, we form an antenna similarily like e.g. in radio communications. This leads to significant local enhancement of the electromagnetic field around the antenna due to resonance effects. Here we meet the enhancement, which is so important for TERS probes. An example of the antenna effect is shown in discussion of [[app:nanoantenna|Plasmonic nanoantenna]]. | ||
| - | The apex also size contributes to the enhancement, by the lighting rod effect, based on its curvature. | + | The apex also size contributes to the enhancement, by the lighting rod effect, based on its curvature, like shown in the following figure: |
| + | |||
| + | {{ :app:ters_both.png?600 |}} | ||
| + | |||
| Finally, we want to see a plasmonic field enhancement, a resonance effect if we use probe and sample that match together. This is however happening only in some measurements, as we often measure on materials that have not this ideal properties. | Finally, we want to see a plasmonic field enhancement, a resonance effect if we use probe and sample that match together. This is however happening only in some measurements, as we often measure on materials that have not this ideal properties. | ||
| Line 17: | Line 21: | ||
| Staircasing effect can create some extra errors, namely for coarse models. | Staircasing effect can create some extra errors, namely for coarse models. | ||
| - | Nevertheless, we can simulate all the typical effects observed at TERS probes. We focused on aluminium coated silicon probes and first wanted to separate different competing effects, as follows | + | Nevertheless, we can simulate all the typical effects observed at TERS probes. In the example here we focused on aluminium coated silicon probes. |
| - | The smaller the tip radius is the bigger is the enhancement. | + | |
| - | The bigger is the thickness of aluminium layer, the bigger is the enhancement in our spectral region of interest | + | |
| - | + | ||
| - | A series of numerical experiments was done to see these effects separately and combined. First, probes from solid aluminium were simulated, having different radii. Second, probes with the same total radius were simulated, having different thickness of the aluminium layer (so the silicon core radius) was changing appropriately. Finally, the most realistic case which are probes with silicon core of some radius with thin film of varying thickness on top was simulated. The simulations were peformed for different wavelengths and also for different materials of the core. | + | |
| ---- | ---- | ||
app/ters.txt · Last modified: 2018/02/02 10:32 by pklapetek
Except where otherwise noted, content on this wiki is licensed under the following license: CC Attribution-Noncommercial 4.0 International
