Dielectric chiral metasurfaces for enhanced circular dichroism spectroscopy at near infrared regime

Asif Ali, Hafiz Saad Khaliq, Aqsa Asad, Jehan Akbar, Muhammad Zubair*, Muhammad Qasim Mehmood*, Yehia Massoud*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Numerous applications of chiro-optical effects can be found in nanophotonics, including imaging and spin-selective absorption, particularly in sensing for separating and detecting chiral enantiomers. Flat single-layer metasurfaces composed of chiral or achiral sub-wavelength structures offer unique properties to manipulate the light due to their extraordinary light-matter interaction. However, at optical wavelengths, the generation of strong chirality is found to be challenging via conventional chiral metasurface approaches. This work intends to design and optimize a dielectric chiral meta-nano-surface based on a diatomic design strategy to comprehend giant chiro-optical effects in the near-infrared (NIR) regime for potential application in circular dichroism (CD) spectroscopy. Instead of using a single chiral structure that limits the CD value at optical wavelengths, the proposed metasurface used a diatomic (two meta-atoms with distinct geometric parameters) chiral structure as a building block to significantly enhance the chiro-optical effect. Combining both meta-atoms in a single periodicity of the building block introduces constructive and destructive interferences to attain the maximum circular dichroism value exceeding 75%. Moreover, using multipolar resonance theory, the physics behind the generation of giant chiro-optical effects have also been investigated. The proposed dielectric chiral meta-platform based on the extra degree of freedom can find application in compact integrated optical setups for CD spectroscopy, enantiomer separation and detection, spin-dependent color filters, and beam splitters.

Original languageEnglish (US)
Pages (from-to)20958-20965
Number of pages8
JournalRSC ADVANCES
Volume13
Issue number30
DOIs
StatePublished - Jul 12 2023

Bibliographical note

Publisher Copyright:
© 2023 The Royal Society of Chemistry.

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering

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