Retrieving orbital angular momentum distribution of light with plasmonic vortex lens

Area of Science:

• Optics and Photonics
• Plasmonics
• Light-Matter Interactions

Background:

• Orbital angular momentum (OAM) is a key property of light.
• Characterizing OAM states, especially complex ones, is crucial for optical communications and microscopy.
• Existing methods can be complex or limited in measuring hybrid OAM states.

Purpose of the Study:

• To develop a novel method for retrieving the orbital angular momentum (OAM) distribution of light.
• To demonstrate the capability of a plasmonic vortex lens (PVL) for OAM analysis.
• To enable simultaneous measurement of relative amplitude and phase for OAM modes, including hybrid states.

Main Methods:

• Utilized a plasmonic vortex lens (PVL) to couple OAM modes of light to surface plasmon polaritons (SPPs).
• SPPs were excited in forms of Bessel functions corresponding to different OAM modes.
• Decomposed the interference pattern of SPPs into Bessel functions to retrieve OAM information.

Main Results:

• Successfully retrieved the OAM distribution of light using the PVL.
• Demonstrated simultaneous retrieval of relative amplitude and relative phase of input OAM modes.
• Showcased the ability to measure hybrid OAM states in a single measurement.

Conclusions:

• The PVL provides an integrated and efficient approach for OAM analysis.
• This method simplifies the characterization of complex light beams.
• The technique holds promise for advanced optical metrology and information processing.