
Second Harmonic Generation Imaging206
e convolution formulation of the propagation, despite the fact of being a little bit more time con-
suming in computing, has several advantages over the FFT version. Indeed, the elds in the hologram
and image plane have the same sampling step. is means that the size of the propagated image is at the
same scale as the one in the hologram plane. is is illustrated in Figure 9.5b, where the size (in pixel) of
the reconstructed image has the same size, independently of the reconstruction distance. Probably for
that reason alone, it is the most widely used implementation.
9.4.1.4 Single 2D Fourier Transfor