Optical orbital angular momentum conservation during the transfer process from plasmonic vortex lens to light

Area of Science:

• Optics and Photonics
• Nanotechnology
• Condensed Matter Physics

Background:

• Surface plasmon polaritons (SPPs) are electromagnetic waves confined to metal-dielectric interfaces.
• Plasmonic vortex lenses (PVLs) are nanostructures capable of shaping light.
• Orbital angular momentum (OAM) is a property of light related to its helical phase front.

Purpose of the Study:

• To demonstrate the conservation of optical orbital angular momentum (OAM) during the generation of SPPs using PVLs.
• To investigate the transfer of OAM from incident light to SPPs.
• To explore the tunability of SP vortices generated by PVLs.

Main Methods:

• Illumination of subwavelength PVLs with light beams carrying OAM.
• Generation and characterization of surface plasmon (SP) vortices.
• Analysis of OAM transfer and conservation.

Main Results:

• Demonstration of OAM conservation in the SPP generation process.
• Generation of SP vortices that inherit the OAM of both the incident light and the PVLs.
• Tunable OAM of the generated SP vortices by controlling PVL structure and incident light OAM.

Conclusions:

• The study confirms OAM conservation in the PVL-SPP interface.
• Generated SP vortices offer a new route for manipulating light at the subwavelength scale.
• Potential applications in nanophotonics, optical trapping, and information processing.