Dynamically Encircling Exceptional Points in Different Riemann Sheets for Orbital Angular Momentum Topological Charge...

Area of Science:

• Photonics
• Integrated Optics
• Optical Communications

Background:

• Orbital angular momentum (OAM) offers an extra degree of freedom for optical communication.
• On-chip manipulation of OAM is essential for integrated photonics.
• Existing methods lack effective on-chip OAM topological charge conversion.

Purpose of the Study:

• To propose an effective on-chip method for OAM topological charge conversion.
• To demonstrate chiral OAM conversion based on exceptional points.
• To provide a new tool for manipulating OAM in integrated photonic devices.

Main Methods:

• Utilizing encircling of two groups of exceptional points in different Riemann sheets.
• Employing adiabatic and non-adiabatic mode evolution in two on-chip waveguides.
• Leveraging chiral behavior where path direction dictates topological charge.

Main Results:

• Achieved on-demand OAM conversion through controlled mode evolution.
• Demonstrated chiral OAM conversion, linking path direction to topological charge.
• Presented a novel method for on-chip OAM manipulation.

Conclusions:

• The proposed method offers an effective solution for on-chip OAM conversion.
• Chiral OAM conversion provides significant advantages for optical systems.
• This work opens new avenues for advanced integrated photonic devices.