Simultaneous detection of spin and orbital angular momentum of light through scattering from a single silver nanowire

TL;DR

This paper presents a novel method for simultaneously detecting the spin and orbital angular momentum of light using elastic scattering from a single silver nanowire, analyzed via Fourier plane microscopy, avoiding complex fabrication.

Contribution

It introduces a simple, nanowire-based approach for concurrent SAM and OAM detection, advancing fundamental understanding and potential on-chip applications.

Findings

Successful unambiguous detection of SAM and OAM states

Analysis of energy flow and scattering characteristics

First example of single nano-object based detection

Abstract

In recent times the spin angular momentum (SAM) and orbital angular momentum (OAM) of light have gained prominence because of their significance in optical communication systems, micromanipulation, sub-wavelength position sensing. To this end, simultaneous detection of SAM and OAM of light beam is one of the important topics of research from both application and fundamental spin-orbit interaction (SOI) point of view. While interferometry and metasurface based approaches have been able to detect the states, our approach involves elastic scattering from a monocrystalline silver nanowire for the simultaneous detection of SAM and OAM state of a circularly polarized Laguerre-Gaussian (LG) beam. By employing Fourier plane (FP) microscopy, the transmitted scattered light intensity distribution in the FP is analyzed to reconstruct the SAM and OAM state unambiguously. The SAM and OAM induced transverse energy flow as well as the polarization dependent scattering characteristics of the nanowire is investigated to understand the detection mechanism. Our method is devoid of complex nanofabrication techniques required for metasurface based approaches and to our knowledge, is a first example of single nano-object based simultaneous SAM and OAM detection. The study will further the understanding of SOI effects and can be useful for on-chip optical detection and manipulation.