Characterization of Orbital Angular Momentum Quantum States Empowered by Metasurfaces

Area of Science:

• Quantum Optics
• Photonics
• Metamaterials

Background:

• Orbital angular momentum (OAM) in twisted photons offers significant potential for quantum communication and fundamental physics tests.
• Current methods for characterizing OAM quantum states face limitations in miniaturization.
• Metasurfaces provide advanced optical field manipulation capabilities for quantum photonics.

Purpose of the Study:

• To present a novel scheme for reconstructing the density matrix of orbital angular momentum (OAM) quantum states of single photons.
• To demonstrate the use of all-dielectric metasurfaces for OAM state characterization.
• To measure the Schmidt number of OAM entanglement using multiplexing techniques.

Main Methods:

• Utilized all-dielectric metasurfaces composed of birefringent meta-atoms.
• Developed a scheme for the reconstruction of OAM quantum state density matrices.
• Employed multiplexing of multiple degrees of freedom to measure the Schmidt number.

Main Results:

• Successfully reconstructed the density matrix of OAM quantum states of single photons.
• Demonstrated the capability of metasurfaces for OAM state characterization.
• Measured the Schmidt number of OAM entanglement.

Conclusions:

• The proposed metasurface-based scheme offers a pathway for miniaturized OAM quantum state characterization.
• This work contributes to the practical application of quantum metadevices for OAM measurements.
• The findings are significant for free-space quantum imaging and communication applications.