Atom of Ernest Rutherford, bombarded a metal foil with alpha particles to observe how they scattered. They expected all the alpha particles to pass straight through with little deflection, because Thomson's model said that the charges in the atom are so diffuse that their electric fields could not affect the alpha particles much. However, Geiger and Marsden spotted alpha particles being deflected by angles greater than 90°, which was supposed to be impossible according to Thomson's model. To explain this, Rutherford proposed that the positive charge of the atom is concentrated in a tiny nucleus at the center of the atom.
Atom laser an optical and an atom laser are that atoms interact with themselves, cannot be created as photons can, and possess mass whereas photons do not (atoms therefore propagate at a speed below that of light). The van der Waals interaction of atoms with surfaces makes it difficult to make the atomic mirrors, typical for conventional lasers. A pseudo-continuously operating atom laser was demonstrated for the first time by Theodor Hänsch, Immanuel Bloch and Tilman Esslinger at the Max Planck Institute for Quantum Optics in Munich. They produce a well controlled continuous beam spanning up to 100 ms, whereas their predecessor