Fig. 3: Illustration of the broadband Fourier transform holography method.

a Each cross-correlation term is transformed into Fourier space by applying an fast Fourier transform (FFT) (b), where a binary filter is applied (small inset), which preserves the high-resolution spatial frequencies. The spatial frequencies are summed and yield a high-resolution Fourier space image which is shown in c. d An enlarged smeared cross-correlation term before the broadband Fourier transform holography (FTH) method was applied and e shows the result of the broadband FTH method. The scalebar in d corresponds to 1 µm and is shared for d and e. The amplitude and intensity is given in arbitrary units (a.u.).