  Quantum entanglement is a fundamental resource for quantum information
processing and is widely used in quantum communication, quantum computation and
quantum metrology. Early research on quantum entanglement mainly focus on qubit
states, but in recent years, more and more research has begun to focus on
high-dimensional entangled states. Compared with qubit entangled states,
higher-dimensional entangled states have a larger information capacity and the
potential to realize more complex quantum applications. In this Letter, we have
experimentally prepared a special high-dimensional entangled state, the
so-called three-photon asymmetric maximally entangled state, which consists of
two two-dimensional photons and one four-dimensional photon. Using this
asymmetric maximally entangled state as a resource, we have also implemented a
proof-of-principle quantum teleportation experiment, realizing the transfer of
quantum information from two qubits to a single ququart. The fidelities of the
quantum teleportation range from 0.79 to 0.86, which are well above both the
optimal single-copy ququart state-estimation limit of 2/5 and maximal
qutrit-ququart overlap of 3/4, thus confirming a genuine and nonclassical
four-dimensional teleportation. The asymmetric entangled state realized here
has the potential to be used as a quantum interface in future quantum networks,
allowing quantum information transfer between quantum objects of different
dimensions via the quantum teleportation protocol demonstrated in this work.
