Reconfigurable vortex beam generator based on the Fourier transformation principle

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Quantum Optics

Background:

• Optical vortex beams carry orbital angular momentum (OAM), enabling advanced applications.
• Precise control over OAM superposition is crucial for optical communication and sensing.
• On-chip generation of OAM states offers miniaturization and integration benefits.

Purpose of the Study:

• To propose and demonstrate a method for generating optical vortex beams with arbitrary OAM superposition on a photonic chip.
• To enable on-demand control of OAM components in integrated photonic devices.
• To provide a feasible platform for manipulating vortex beams and detecting OAM states.

Main Methods:

• Utilizing the Fourier transformation principle to control OAM components via incident light phases.
• Designing and fabricating a photonic chip device incorporating nine Fourier holographic gratings.
• Characterizing the generated optical vortex beam's OAM states and working bandwidth.

Main Results:

• Successfully generated optical vortex beams with controllable OAM states ranging from -2 to +2.
• Achieved an 80 nm working bandwidth for the OAM control.
• Demonstrated the feasibility of on-demand OAM manipulation on a photonic chip.

Conclusions:

• The proposed method offers a practical approach for generating arbitrary OAM superpositions on-chip.
• This technology facilitates advanced manipulation and detection of vortex beams in integrated photonics.
• The developed device serves as a key component for future photonic integrated circuits enabling complex OAM functionalities.