Rapid readout of terahertz orbital angular momentum beams using atom-based imaging

Area of Science:

• Optics and Photonics
• Quantum Information Science

Background:

• Terahertz (THz) beams carrying orbital angular momentum (OAM) offer unique properties for advanced applications.
• Efficient and rapid readout of THz OAM modes is crucial for their practical implementation.

Purpose of the Study:

• To demonstrate a novel, rapid imaging technique for reading out terahertz OAM beams.
• To enable high-fidelity characterization of complex OAM modes, including azimuthal and radial indices.

Main Methods:

• Generation of THz OAM beams with controlled azimuthal and radial indices using phase-only plates.
• Terahertz-to-optical conversion within an atomic vapor medium.
• Far-field imaging of the converted optical signal using a CCD camera.
• Utilizing self-interferogram patterns for direct readout of azimuthal index sign and magnitude.

Main Results:

• Successful rapid readout of terahertz OAM modes with high fidelity in 10 milliseconds.
• Demonstration of distinguishing OAM modes based on both azimuthal and radial indices.
• Capability to read out low-intensity terahertz OAM beams.

Conclusions:

• The atomic-vapor-based imaging technique provides a fast and reliable method for terahertz OAM beam readout.
• This advancement is expected to significantly impact the development of terahertz communications and microscopy.
• The technique's ability to resolve complex OAM modes opens new avenues for THz technologies.