Fourier Transform, Optical Computing, Free Space Optics.
the 1D transforms differ. They both involve multiplication by complex numbers with unit modulus, called ‘twiddle factors’, and some data rearrangement. Let us start with Cooley-Tukey. For each ​(j,k)​, we define the array b⁽ʲ ᵏ⁾​ with shape ​(nx,ny) by: The two exponentials in the right-hand side