Large Enhancement of Circular Dichroism Using an Embossed Chiral Metamaterial

Mousavi, S. Hamed Shams; Panikkanvalappil, Sajanlal R.; El‐Sayed, Mostafa A.; Eftekhar, Ali A.; Adibi, Ali

doi:10.48550/arxiv.1604.05244

Cited by 2 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…P lasmonic nanostructures with broken symmetry can show different electromagnetic response to left-and righthanded circularly polarized (LCP and RCP, respectively) light. 1−11 The different responses can be observed in both transmission 2,3 and reflection, 12 and the difference between the reflected (or transmitted) power under LCP and RCP illumination is often referred to as circular dichroism (CD), 2 which is a measure of the selectivity of the structure in interacting with the sense of handedness of the incident light. The concept of the CD used to describe artificially made nanostructures 2,6,13,14 is borrowed from the field of stereochemistry and is defined as the difference between the absorbance of LCP and RCP illumination by chiral molecules, 15−18 molecules that are not superimposable on their mirror-image by any rotation or translation.…”

mentioning

confidence: 99%

Giant Circular Dichroism at Visible Frequencies Enabled by Plasmonic Ramp-Shaped Nanostructures

et al. 2019

View full text Add to dashboard Cite

Plasmonic nanostructures with spatial symmetry breaking have a variety of applications, from enhancing the enantioselective detection of chiral molecules to creating photonics devices such as circular polarizers. Compared to their molecular counterparts, engineered nanostructures exhibit orders of magnitude larger circular dichroism (CD) at optical frequencies. Although 3D nanostructures such as nanohelices have been reported with high CD at mid-IR frequencies, such high CDs have not yet been achieved at visible frequencies with decent efficiencies. Here, we propose a planar array of plasmonic ramp-shaped nanostructures with an azimuthally gradient depth that exhibits a giant CD and dissymmetry factor at visible frequencies. The structure is fabricated on a gold-coated glass slide using focused ion beam (FIB) with gradient intensity to induce the required gradient depth, hence, breaking symmetry. Optical experimental characterization in the reflection spectrum shows a CD up to 64% and a dissymmetry factor up to 1.13 at 678 nm, in a good agreement with numerical simulations. We envision our proposed structure together with the suggested fabrication method to inspire the design of novel optical devices such as nanoscale circular polarizers and a host of chiral molecules to improve enantioselectivity in the pharmaceutical industry.

show abstract

mentioning

confidence: 99%

Giant Circular Dichroism at Visible Frequencies Enabled by Plasmonic Ramp-Shaped Nanostructures

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Two well-known quantities that are used in the characterization of chiral media are CD and the dissymmetry factor (or the g-factor). 41,47,78,79 They are the two analogous criteria to measure the difference between the extinction of a material under two illuminations with the opposite optical helicity (i.e., EM field chirality), typically using both right-hand CP (RCP) and left-hand CP (LCP) light (ref 80, Section 11),. 42,43,81,82 In practice, the difference between the transmittance spectra for an RCP light illumination and an LCP light illumination is used in the determination of the sample's chirality.…”

Section: Experiments and Metasurface Propertiesmentioning

confidence: 99%

Classification of Bianisotropic Metasurfaces from Reflectance and Transmittance Measurements

et al. 2023

View full text Add to dashboard Cite

Using fundamental electromagnetic properties of metasurfaces, we build a platform to classify reciprocal bianisotropic metasurfaces from typical experimental measurements and determine isotropic, anisotropic, bi-isotropic (chiral), and bianisotropic (so-called omega) properties. We provide experimental guidelines to identify each class by measuring macroscopic scattering parameters, that is, reflection and transmission coefficients upon plane wave illumination with linear and/or circular polarization. We explicitly provide a recipe of which metasurface properties can and cannot be inferred by means of the chosen polarization, reflection, and transmission properties. We also clarify common confusions in the classification of anisotropic versus chiral metasurfaces based on circular dichroism measurements presented in the recent literature.

show abstract

Large Enhancement of Circular Dichroism Using an Embossed Chiral Metamaterial

Cited by 2 publications

References 0 publications

Giant Circular Dichroism at Visible Frequencies Enabled by Plasmonic Ramp-Shaped Nanostructures

Giant Circular Dichroism at Visible Frequencies Enabled by Plasmonic Ramp-Shaped Nanostructures

Classification of Bianisotropic Metasurfaces from Reflectance and Transmittance Measurements

Contact Info

Product

Resources

About