Translator Disclaimer
22 January 2020 Purity and efficiency of hybrid orbital angular momentum-generating metasurfaces
Author Affiliations +
Abstract

Controlling light with subwavelength-designed metasurfaces (MSs) has allowed for the arbitrary creation of structured light by precisely engineered matter. We report on the purity and conversion efficiency of hybrid orbital angular momentum (OAM)-generating MSs. We use a recently reported method to design and fabricate meta-surfaces that exploit generalized spin-orbit coupling to produce vector OAM states with asymmetric OAM superpositions, e.g., 1 and 5, coupled to linear and circular polarization states, fractional vector OAM states with OAM values of 3.5 and 6.5, and also the common conjugate spin and OAM of ±1 as reported in previous spin-orbit coupling devices. The OAM and radial modes in the resulting beams are quantitatively studied by implementing a modal decomposition approach, establishing both purity and conversion efficiency. We find conversion efficiencies exceeding 75% and purities in excess of 95%. A phase-flattening approach reveals that the OAM purity can be very low due to the presence of undesired radial components. We characterize the effect and illustrate how to suppress the undesired radial modes.

© 2020 Society of Photo-Optical Instrumentation Engineers (SPIE) 1934-2608/2020/$28.00 © 2020 SPIE
Bereneice Sephton, Yao-Wei Huang, Antonio Ambrosio, Cheng-Wei Qiu, Adam Vallés, Takashige Omatsu, Federico Capasso, and Andrew Forbes "Purity and efficiency of hybrid orbital angular momentum-generating metasurfaces," Journal of Nanophotonics 14(1), 016005 (22 January 2020). https://doi.org/10.1117/1.JNP.14.016005
Received: 3 September 2019; Accepted: 4 December 2019; Published: 22 January 2020
JOURNAL ARTICLE
15 PAGES


SHARE
Advertisement
Advertisement
Back to Top