In this master's thesis Cross-Differential Dynamic Microscopy is introduced as an extension to the established method of Differential Dynamic Microscopy, for the purpose of observing the fast dynamics in soft matter. With the standard method, a video of the fluctuating intensity of light, scattered by the observed sample, is taken at a constant frame rate. The smallest time delay between two consecutive frames is therefore inversely proportional to the frame rate. With the new method we obtain two sets of data, taken with two aligned cameras observing the same area in the sample, and we calculate the cross-image structure function as a function of the wave vector and the time delay. Random triggering of the cameras can greatly decrease the minimum time delay between the two frames, which results in a faster effective frame rate. This way we can observe the dynamics of fast processes in soft matter. In the experiment we compared both the standard and the new method by measuring the dynamics of a nematic liquid crystal and by analyzing simulated videos of Brownian motion of spherical particles. Lastly, robustness of the proposed method was tested against various camera misalignments.
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