Complete Redesign

[roflmaostc]

This projects definitely needs a redesign. It should be CUDA compatible and also differentiable by automatic differentiation!

First, I want to focus (:zany_face:) on scalar optics.

I think it might make sense to introduce types like:

struct ScalarField{T, N, A <: Union{Array{T, N}, CuArray{T, N}}}
           # wavelength
           λ :: T
           # length of eletrical field
           L :: T 
           # Array, CuArray, ... of 
           field :: A
       end

Those are the trivial parameters we need to describe a field. Scalar Fourier optics is possible with such a type.

[roflmaostc]

I guess we should introduce L1 and L2 to handle non-quadratic fields (different scaled fields) as well?

struct ScalarField{T, N, A <: Union{Array{T, N}, CuArray{T, N}}}
           # wavelength
           λ :: T
           # length of eletrical field in each of the dimensions
           L1  :: T 
           L2 :: T 
           # Array, CuArray, ... of 
           field :: A
       end