Learning Forum

[SAURAV GAUTAM]

hi

i simulated a silicon structure with dimensions 1100 X 1900 X 380 mm.

I placed 1100nm wave source above it and a monitor below the film. But monitor is showing zero value. is it because of total absorbtion of wave by film?

thanks

[Guilin Sun]

Most likely the simulation time is too small. Please use 100 times what you used. Do not worry about the estimated time as it will terminate after fulfilling the autoshutoff min and will stop early. If it stops at 100% it means the simulation time is too small.

 

You can place a time monitor at the same location and check if the time signal completely decays.

 

BTW: usually you do not need to use single frequency, as the source is a pulse in most of the times. The frequency domain result is obtained from the Fourier transform of time signal. If you have questions regarding to this please write a new post.

[SAURAV GAUTAM]

Thank you,

could you give more suggestions for simulating big structure in range 0.5 to 1 mm as simulation is taking long time. my goal is to find out transmission ration in doped silicon film.

[Guilin Sun]

For 1100 X 1900 X 380 mm it is too large for common workstation or cloud to handle at um wavelengh due to hardware limitation and other factors.

If the cross section is relatively small, but the simulation is long along propagation such as metalens, it can simulate only a small distance and the result can be calculated using farfieldexact:

https://optics.ansys.com/hc/en-us/articles/360042160473-Focusing-with-a-single-subwavelength-aperture

https://optics.ansys.com/hc/en-us/articles/360042160493-Bull-s-eye-aperture (please check the script inside the analysis group)

Depending on the frequency points you want, the farfieldexact might be a little slow.

If the cross section is large, you can also refer to the above examples but now the challenge is, you may need a lot of memory and the simulation is slow.

Baiscally the simulation will need to mesh the simulation space into grids and the time step is limited by the smallest mesh size, so for large dimensions more memory and longer simulation time are normal. If your computer is powerful enough, you can use as many as processes (cores) as possible, limited by your license.