Generalized Talbot-Lau Atom Interferometry

Publisher Summary This chapter describes a particular form of a grating interferometer called the generalized Talbot-Lau (GTL) interferometer. The chapter first identifies a significant weakness (low throughput) of its progenitor form, separated beam envelope (SBE) interferometry, outlines the operating principles of the GTL interferometry, and shows how GTL interferometry remedies this weakness. The GTL interferometry is based on a unique form of interference intimately associated with Fresnel diffraction that occurs when Fraunhofer diffraction orders overlap. This effect was originally discovered in the optical domain using lenses and gratings, and is called the Talbot effect. Its diffraction pattern consists of the so-called Fourier and Fresnel fringes that, surprisingly, are actually multiply “aliased” near self-images of a grating's periodic complex amplitude transmission function. The chapter introduces the Talbot effect and gives a brief historical outline of work contributing to its understanding. It also introduces the related Lau effect and the Talbot interferometer. The chapter also shows how these can be combined to create generalized lens-free Talbot-Lau interferometers, suitable for de Broglie wave interferometry.