Quantum simulations of optical systems

Within the framework of a two-dimensional microscopic, purely quantum mecha nical model, we analyse the dynamics of single-photon wave packets interact ing with optical elements (beam splitters, mirrors), modelled as systems of two-level atoms. That is, we utilize a two-dimensional cavity to simulate the quantum behaviour of simple optical components and networks made thereo f. The field is quantized using the canonical procedure, and only the basis states with one unit of excitation are included. This, however, covers lin ear optical phenomena. The field is taken to interact with localized atoms through a dipole interaction. Using different configurations of atoms, and choosing their frequencies to be resonant or off-resonance, we can model mi rrors, beam splitters, focusing devices and multicomponent systems. Thus we can model arbitrary linear networks of optical components. We show the tim e evolution of a photon wave packet in an interferometer as an example. As the state of the field is known at each instant, spectral properties and sp atial coherence can immediately be obtained from the simulations. We also k now the states of the two-level atoms constituting the components, which al lows us to consider their quantum behaviour. Here the decay of an excited a tom into the vacuum state of the electromagnetic field in the two-dimension al cavity is studied.