Learning Forum

[Pak Him Chow]

I was playing with the plasmon mode excitation example from the Lumerical FDTD simulation software, I have successfully simulated the original example, but when I changed the 2 spheres into 2 triangles, I get no results. I have attached a screenshot of the azimuthal source electric field intensity of the 2 trangles with 4nm distance apart.

[Guilin Sun]

From the description it is difficult to provide any help. We do not expect that changing one object you will get expected result. It needs design, eg optimize the location, geometry, dimension and perhapes material etc.

From your result I can see very strong local enhencement. So I do not understand what do you mean "no results".

 

[Pak Him Chow]

 

 

Sorry for being unclear, what I have done was replacing the original spheres with trangles, placing them together with the tips of both trangles distancing 5-10 nm. I was expecting that strong local enhencement would take place around the both tips that are close to each other, but as you can see from the electric field intensity plot, it only happens around the other tips.

I have tried changing the dimensions of the trangles, distance between the tips, material of the trangles, switching to radial source, nothing changes. What can I do in order to see strong local enhencement around the tips where they are close to each other? The reason I want to achieve this is because ultimately I want to place a sphere in between the trangle tips to act as a quantum dot and see the local enhencement occuring around the quantum dot.

 

[Pak Him Chow]

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[Guilin Sun]

Sorry, my yesterday's reply is not submitted successfully.

From your results, it is clear that the enhavement is inside the nano particle instead of at the gap of the tips. This means the excitation is not correct, or the device configuration is not correct. You can use log scale to check the field intensity at the gap. Such device needs careful design. unfortuately it is not that obvious whe things are changed. Please take some time to optimize the device configuration.

I guess it is due to the whipser gallery modes inside each triangle.  Due to symmetry effect, the location of such modes cannot be uniquely positioned, probably due to excitation.  Such personal observation is purely for your reference.