Observation of highly correlated ultrabright biphotons through increased atomic ensemble density in spontaneous four-wave mixing
Abstract
The pairing ratio, a crucial metric assessing a biphoton source's ability to generate correlated photon pairs, remains underexplored despite theoretical predictions. This study presents experimental findings on the pairing ratio, utilizing a double-Λ spontaneous four-wave mixing biphoton source in cold atoms. At an optical depth (OD) of 20, we achieved an ultrahigh biphoton generation rate of up to 1.3 ×107 per second, with a successful pairing ratio of 61%. Increasing the OD to 120 significantly improved the pairing ratio to 89%, while maintaining a consistent biphoton generation rate. This achievement, marked by high generation rates and robust biphoton pairing, holds great promise for advancing efficiency in quantum communication and information processing. Additionally, in a scenario with a lower biphoton generation rate of 5.0 ×104 per second, we attained an impressive signal-to-background ratio of 241 for the biphoton wavepacket, surpassing the Cauchy-Schwarz criterion by approximately 1.5 ×104 times.
- Publication:
-
Physical Review Research
- Pub Date:
- July 2024
- DOI:
- 10.1103/PhysRevResearch.6.L032001
- arXiv:
- arXiv:2312.12758
- Bibcode:
- 2024PhRvR...6c2001S
- Keywords:
-
- Quantum Physics;
- Physics - Atomic Physics;
- Physics - Optics
- E-Print:
- Main text: 6 pages, 4 figures