  Quantum networks and distributed quantum computers rely on entanglement
generation between photons and long-lived quantum memories. For large-scale
architectures, one of the most crucial parameters is the efficiency at which
entanglement can be created and detected. Here, we maximize the efficiency for
the detection of hybrid entanglement between a nuclear spin qubit in diamond
with a photonic time-bin qubit. Our approach relies on an optimal
implementation of the photonic qubit analyzer, for which we use a high-speed
electro-optic deflector to direct photons deterministically along the optimal
interferometer paths. This way, we completely eliminate all cases in which
photons are randomly lost due to the propagation in the wrong interferometer
path. In this first demonstration experiment, we use nitrogen-vacancy center in
diamond, for which we immediately demonstrate the presence of the entanglement.
An extension to other spin-photon entanglement systems is straightforward.
Further, our scheme can be used in the framework of quantum repeater networks,
including spectral and temporal multiplexing strategies. Our results thus pave
the way for the future high-performance quantum networks.
