Learning Forum

[2212296]

Hi, I am running a simulation on transmission coefficient (s-parameters) in the wavelength range of 1-10um.

There are two scan modes: single point scan and point scan within range

Single point scan: set the light source at a certain value between 1-10um

Range scanning: the starting wavelength of the light source is 1um, and the ending wavelength is 10um, taking a certain frequency point

In theory, the result should be the same. However, there is a big difference (redshift or blueshift) Question: Can you better fit the curves of the two?

There is nothing happier to me than to receive your letter

[Guilin Sun]

 

May I know what solver you are referring? FDTD or EME? If it is FDTD, please make sure that you specify the source in wavelength, not in frequency.

For FDTD, since the material fitting (if it is dispersive ) and mesh genration will depend on the wavelength, it is better to fix both of them. You can try this:

 

 

[2212296]

83，84，85always error .How to set it correctly with code instructions?

[Guilin Sun]

 

One thing I forgot to mention: when you sweep wavelength, please sweep both the “wavelength start” and the “wavelength stop” in order to have a single wavelength result.

 

I did a simple test and ensured that both methods give exacly the same result, provided that you have set up the wavelength stop the same as the wavelength start.

 

 

[2212296]

Hello, because the wavelength is 1-10um, the simulation time is too long, so I use 5-10um (frequency 30-60Thz).  

Transmission Spectrum (T = transmission('T'))

1. Scanning: 5-10(um)    61point
2. Single point: 5:(5/60):10(um)     Introduce for loop

 

[2212296]

1. Scanning: 5-10(um)    61point

[2212296]

2.Single point: 5:(5/60):10(um)     Introduce for loop

 

[Guilin Sun]

 

You are sweeping single wavelength but the start and stop wavelengths are not the same, which is wrong!

In most cases you do not need to sweep the wavelength. Instead, you need to use Boradband for mode source here:

You can read out the wavelength and see if they are the same. I am sure if you set correctly the result will be the same.

[2212296]

Hello, the first two replies are two different solutions

[2212296]

Please read my reply completely, thank you！！

[Guilin Sun]

 

You mentioned “point” sweep and “range” sweep”, and I provided solutions. Not only I tested the “range” sweep and “point” sweep, I also tested script loop one wavelength at a time by setting the wavelength “start” and “stop” the same. No any discrepancy among the 3 methods is found. If you found difference, please upgrad to the newest version 2022R2.2.

Please use the sweep utility.

If you have other questions please write a new post, please.

 

 

[2212296]

Your answer makes me feel like a spring breeze.

However the last question is under this answer.

For loop, do I need to set the following picture?

Or the role here is only to cooperate with the wavelength setting of the light source？？For stability?

[Guilin Sun]

I think I replied this question before:

If you do not fix them, the dispersive material may give different refractive index and the mesh is also different from broadband, when you sweep the wavelength