Description
The frequency-correlated biphotons are an excellent resource for long-distance quantum communication. They can be generated from the diamond-type atomic level structures under four-wave mixing in an alkali metal atomic ensemble. The signal photon from the upper transition has low-loss telecom bandwidth useful in a fiber-based quantum network, while the idler photon from the lower transition can be stored locally as a collective spin wave. In contrast to the highly entangled biphotons, an almost indistinguishable single photons with low frequency entanglement are the building blocks in photonic quantum simulation or computation. In this poster we theoretically investigate the frequency entanglement of the biphoton and propose two approaches to remove their mutual correlations in frequency spaces. First, we generate a more symmetric and narrower biphoton spectrum by multiplexing atomic ensembles with phase compensation using optical cavity. The entanglement entropy S of the biphoton reduces to 0.006, which is 200 times smaller than the one without multiplexing and corresponds to the purity of single photon as 0.999. In the other approach, we symmetrically pump two atomic ensembles under non-discrimination detectors, which leads to a moderately reduced S ~ 0.3.
| Presenter name | T. H. Chang |
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| How will you attend ICAP-27? | I am planning on virtual registration for online attendance |
