Deterministic Free-Space Source of Single Photons Using Rydberg Atoms.

Area of Science:

• Quantum optics
• Atomic physics
• Photonics

Background:

• Generating single photons in specific modes is crucial for quantum technologies.
• Existing methods often rely on strong light-matter coupling in cavities or complex heralding mechanisms.
• Rydberg interactions offer a promising avenue for novel quantum light sources.

Purpose of the Study:

• To propose an efficient free-space scheme for generating single photons in a well-defined spatiotemporal mode.
• To leverage Rydberg atom interactions for single-photon generation without relying on cavities or heralding.
• To demonstrate a new approach for creating controllable single-photon sources.

Main Methods:

• Preparing a single source atom in an excited Rydberg state.
• Utilizing laser-mediated dipole-dipole interactions between the source atom and an ensemble of ground-state atoms.
• Employing adiabatic passage with a chirped laser pulse to create a spin wave of Rydberg excitation.
• Converting the collective atomic excitation to a propagating optical photon via a coherent coupling field.

Main Results:

• Successfully generated single photons in a well-defined spatiotemporal mode.
• The scheme operates in free space, avoiding the need for resonant cavities.
• The method does not require heralding of collective excitation or Rydberg blockade.
• Demonstrated an efficient conversion of collective atomic excitation to a single photon.

Conclusions:

• The proposed scheme offers an efficient and robust method for single-photon generation.
• This approach provides an alternative to cavity-based single-photon sources.
• The technique's reliance on Rydberg interactions opens new possibilities for quantum information processing and quantum communication.