Orbital Angular Momentum in Optics

Light carries not only energy but also angular momentum, and beyond the familiar spin associated with circular polarization, beams can possess orbital angular momentum arising from a helical phase structure that causes the wavefront to twist like a corkscrew as it propagates. Controlling and exploiting this property has opened practical paths to trapping and rotating microscopic particles with optical tweezers, sorting cells in microfluidic devices, and encoding information in quantum communication systems where each distinct twist state represents an independent channel. Researchers are actively working to extend these techniques down to the nanoscale using plasmonic structures that concentrate light far below the diffraction limit, and to better understand how orbital and spin angular momentum exchange in complex, structured light fields. Key open questions include how to generate and detect high-purity orbital angular momentum states with minimal crosstalk in turbulent or scattering media, and how to integrate these tools reliably into scalable photonic and biological systems.

Works

60,983

Total citations

1,001,624

Keywords

Optical ManipulationOrbital Angular MomentumLight BeamsOptical TweezersStructured LightPlasmonic Nano-optical Tweezers