subwavelength hole simulation

[ALEXCHEN]

Hello , I have installed the 32bits version of OPTIFDTD and design a subwavelength hole periodic structure ,
and settings are based on lesson 15 of 32bits_tutorial.pdf except the script part.

According to the tutorial I would like to calculate the power transmission spectrum , but the result shows some value is higher than 1 ,
even normalize to the input plane .

After tuning the input plane setting , mesh , time interval , even the APML boundary condition ( though I don’t quite know the meaning of tensor parameter and grading polynomial ) , but I can’t have the result that power transmission spectrum lower than 1.

After that I have read the forum and search for some answer and found someone had the same question but no clear setting can be found.

I upload the design file and hope I can have some help here , thank you very much.

[Scott Newman]

Hello Alex,

One thing to note is that with the Fourier transforms on a the Gaussian pulse, the further you go away from the central wavelength the less accurate your results are. Your source is 0.55 um and you are running Fourier transforms from 0.3 to 1.1 um. With the 64-bit product I only find the value going over one if I move away from the central wavelength.

Based on the information you have made available it would appear that you are dealing with one of two situations:
1. You are running into a bug that is specific to the 32-bit free product which is out-dated and not currently maintained.
2. You are looking at values that are to far from your central wavelength based on your pulse width.

Scott

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