# Getelectric and visualizer electric field

#1

Two simulations have same plot(|E|^2 vs wavelength).
(I use command ‘getelectric’ and ‘integrate2’.)
And visualizers of E have also similar.

first,
According to the visualizer, summation of |E|^2 is different in the same size.
So, total summation of |E|^2will be different.
But, I calculate total |E|^2 using codes ‘getelectric’ and ‘ integrate2’.
Of course I know that they have to be same and result is same.
I just wonder that how they calculate and show the image of |E|^2.

second,
There are lots of different value between the value in visualizer and the value in calculation.
Why do they have a difference? What is the unit?

#2

Dear @jaesunglee

It is good that the results of the coarse and fine meshes agree. This means that value of |E|^2 is consistent between the two simulations. If they didn’t match, you would need to perform convergence testing.

integrate2 numerically sums up all the values of |E|^2 over the area of interest. In your calculation, you need to multiply |E|^2 by the area, which is 4 times the finer mesh for properly summing up the values. To be more clear, lets say that the size of each square in small mesh is 1nm^2 (which will be 4 nm^2 for big square)

Large mesh: 0.6 *4 = 2.4
small mesh: 0.6*1 + 0.6*1 + 0.6*1 + 0.6*1 =2.4