Experimental generation of 2000-mode entangled graph states

Expanding the size of spatial multi-partite entangled states is extremely challenging and inefficient. Recently, N. C. Menicucci et al. proposed two solutions for this problem whereby modes are encoded in an optical frequency modes or temporal modes. Although the generated states are equivalent mathematically, experimentally they are quite different. In both schemes, arbitrarily large entangled states can in principle be generated with an experimentally feasible setup. Here, we present the experimental generation of very large entangled graph states by encoding the modes temporally.