Abstract
Although frequency multiplexing of information has revolutionized the field of classical communications, the color degree of freedom (DOF) has been used relatively little for quantum applications. We experimentally demonstrate a new hybrid quantum gate that transfers polarization entanglement of nondegenerate photons onto the color DOF. We create, for the first time, high-quality, discretely color-entangled states (with energy band gap up to 8.4 THz) without any spectrally selective filtering, and unambiguously verify and quantify the amount of entanglement (tangle, 0.611 +/- 0.009) by reconstructing a restricted density matrix; we generate a range of maximally entangled states, including a set of mutually unbiased bases for an encoded qubit space. The technique can be generalized to transfer polarization entanglement onto other photonic DOFs, like orbital angular momentum.
Original language | English |
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Article number | 253601 |
Number of pages | 4 |
Journal | Physical Review Letters |
Volume | 103 |
Issue number | 25 |
DOIs | |
Publication status | Published - 18 Dec 2009 |
Keywords
- QUANTUM COMMUNICATION
- PHOTON PAIRS
- INTERFERENCE
- TIME
- MOMENTUM
- ENERGY
- STATES