Optical Transform Properties
Electric field at the BaTiO3 is the Fourier transform of the electric field in the sample cell; Ein(wx,wy) ? F{E(x0,y0)}
The lens focuses the relatively large probe laser to a small spot at the BaTiO3 producing a ?-function-like rejection filter
The focused excitation laser produces a small-diameter, imaginary transmission perturbation
The small imaginary transmission results in a real, large-diameter beam perturbation at the BaTiO3