Quantum Teleportation of Information with Two Photon Pairs Link to: POSTER
The realization of faithful transmission of information in quantum communication, completely secure information exchange in quantum cryptography, and exponentially faster speeds in quantum computing fundamentally require an entangled state of the Bell type. The twine photons produced by spontaneous parametric down conversion (SPDC) via a pump photon interacting with a β-barium borate, BaB2O4 (BBO) nonlinear crystal are the most common source of a Bell-type entangled state. Due to the conservation of energy and the conservation of momentum, the twine photons are typically entangled in their spatial and spectral degrees of freedom, which have been used in many applications of entanglement.
In our study, we focus on a single BBO crystal that generates polarization-entangled photons under type-II parametric down conversion, in which the down converted photons are emitted into two cones: one horizontally polarized (h), the other vertically polarized (v). In the region where the cones overlap, the two spectrally multimode photons exist in a polarization entangled state. Thus, the correlated photons are produced in an entangled state of the form |h,v〉+|v,h〉. We analyze the degree of entanglement of the twine photons and then measure the teleportation fidelity. Then, using the relationship we discover between the two entangled photons, we use two pairs of entangled photons which have been interacted with each other to measure the degree of entanglement through entanglement swapping, and compare this result with the result for the initial pair of photons. We then use these results to further learn of the teleportation fidelity for two pairs of entangled photons, and compare our findings with those for the teleportation fidelity of a single pair.