Quantum Entanglement of High Angular Momenta (Ohne Sprachangabe)

Entanglement is a key feature in quantum information science and plays an important role in various applications of quantum mechanics. Fickler et al. (p. 640) present a method for converting the polarization state of photons into information encoded into spatial modes of a single photon. From this, superposition states and entangled photons with very high orbital angular momentum quantum numbers were generated.

A method to entangle photons with very-high–orbital angular momentum quantum numbers advances quantum information science.

Single photons with helical phase structures may carry a quantized amount of orbital angular momentum (OAM), and their entanglement is important for quantum information science and fundamental tests of quantum theory. Because there is no theoretical upper limit on how many quanta of OAM a single photon can carry, it is possible to create entanglement between two particles with an arbitrarily high difference in quantum number. By transferring polarization entanglement to OAM with an interferometric scheme, we generate and verify entanglement between two photons differing by 600 in quantum number. The only restrictive factors toward higher numbers are current technical limitations. We also experimentally demonstrate that the entanglement of very high OAM can improve the sensitivity of angular resolution in remote sensing.