Optimization of collection optics for maximum fidelity in entangled photonsources

Authors : Kadir DURAK

Pages : 528-538

View : 21 | Download : 8

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :In this report, decoherence sources for entangled photons created by spontaneous parametric down-conversionphenomenon are studied. The phase and spatial distinguishability of photon pairs from orthogonal crystals reduce themaximum achievable entanglement fidelity. Carefully chosen compensation crystals are used to erase the phase andspatial traces of down-conversion origins. Emission angle of photon pairs also leads to optical path difference and resultsin phase distinguishability. A realistic scenario is numerically modelled, where the photon pairs with nonzero emissionangle gather a phase difference. These pairs can still be collected and manipulated for practical use but the collectionoptics adds upon the phase difference. Two commercially available optics for collection; aspheric and achromatic lensesare compared. The numerical simulation results are compared with the experimental results to validate the built modelfor predicting the maximum achievable entanglement fidelity. The results indicate that the fidelity can be accuratelyestimated with the presented model by inserting the experimental parameters to it. The study is expected to be veryuseful for preparation and optimization of entangled photon pair sources in critical phase-matching configuration.
Keywords : Entanglement fidelity, optics, photon pair sources, quantum optics