## Topic 4: Advanced Elastic Diffraction

#### Part A: Sum of Fourier series

Associated videos: Thin film diffraction

A.1 - We'll start by considering the Fourier transform of an infinite sum of Gaussians, and then see how this changes with series size.

A.2 - Now let's create a film of different lattice spacing than the substrate and consider its transform as a function of thickness. Note the Laue fringes and intensity.

A.3 - If we have two 'domains' of dirac combs with different spacing, what is the Fourier transform? This can be solved analytically.

A.4 - We'll explore different diffraction scans using props for k and k' and ball/stick models for crystal substrates/films.