An interactive visual interface for the determination of similarity patterns in the Fourier spatial frequency spectrum of laser speckle

Laser speckle from particles that are smaller than the wavelength of light resemble a random Gaussian field, but can be shown to contain a characteristic spectrum in frequency space. Speckle is caused by not only the instantaneous microstructure of nanoparticles in suspension that will fluctuate as they reorganize, but also by the magnetic and optical properties of the scattering medium itself. Here we demonstrate interactive tool that can be used to define similarities between seemingly random scattering fields. Optimization of the Fourier spatial frequency spectrum gives a representative pattern that can be directly correlated to the transport properties of the particles.