Non-degenerated nonclassical photon pairs in a hot atomic ensemble

Area of Science:

• Quantum Optics
• Atomic Physics
• Nonlinear Optics

Background:

• Nonclassical light sources are crucial for quantum information processing.
• Generating entangled photon pairs in atomic ensembles offers a promising scalable approach.

Purpose of the Study:

• To experimentally demonstrate the generation of non-degenerate nonclassical paired photons.
• To characterize the photon pairs using second-order correlation functions.
• To verify the nonclassical nature of the generated photons by violating the Cauchy-Schwarz inequality.

Main Methods:

• Utilizing off-axis four-wave mixing in a hot atomic ensemble.
• Measuring the time-resolved second-order correlated function (g(2)) between Stokes and anti-Stokes photons.
• Analyzing the photon correlation to assess the violation of the Cauchy-Schwarz inequality.

Main Results:

• Successfully generated non-degenerate nonclassical paired photons.
• Measured a two-photon correlation value of 1.87 ± 0.04.
• Observed a violation of the Cauchy-Schwarz inequality by a factor of 1.69 ± 0.14, confirming nonclassicality.

Conclusions:

• The experiment confirms the feasibility of generating nonclassical photon pairs in hot atomic ensembles.
• The observed violation of the Cauchy-Schwarz inequality provides robust evidence for the nonclassical nature of the generated light.
• This work paves the way for developing robust and scalable sources of nonclassical light for quantum technologies.