Probing the negative Wigner function of a pulsed single photon point by point

Area of Science:

• Quantum optics
• Quantum information science
• Photonics

Background:

• Investigating quantum properties of light is crucial for quantum technologies.
• Characterizing non-classical states of light, like single photons, is experimentally challenging.

Purpose of the Study:

• To probe the quantum properties of pulsed light fields in phase space.
• To experimentally verify the negative region of the Wigner function for a single photon.

Main Methods:

• Utilizing waveguided parametric down conversion to generate single photons.
• Employing loss-tolerant photon-number resolving detection.
• Displacing the quantum state in phase space to observe photon statistics.

Main Results:

• Direct observation of oscillations in photon statistics.
• Successful probing of the negative region of the Wigner function.
• Demonstration of high mode sensitivity in the detection scheme.

Conclusions:

• The developed method allows for detailed point-by-point investigation of quantum states in phase space.
• The scheme confirms the non-classical nature of generated single photons.
• The technique can identify the single-mode character of quantum light states.