Cholesteric spherical reflectors as innovative optical elements with vast application potential

anti-counterfeiting; Bragg diffraction; Cholesteric liquid crystals; fiducial markers; retroreflector; structural color; Anti-counterfeiting; Cholesteric liquid-crystal; Cholesterics; Fiducial marker; Optical-; Orientational orders; Retro-reflectors; Self-assemble; Structural color; Electronic, Optical and Magnetic Materials; Condensed Matter Physics; Computer Science Applications; Applied Mathematics; Electrical and Electronic Engineering

Abstract :

[en] Cholesteric Spherical Reflectors (CSRs) are omnidirectional selective retroreflectors enabled by the ability of cholesteric liquid crystals (CLCs) to self-assemble with helicoidally modulated long-range orientational order, turning them into a liquid chiral photonic crystal with one-dimensional periodicity. The liquid state allows us to easily mold the CLC into spherical units, with stabilizers in the surrounding liquid phases ensuring the appropriate boundary conditions. By varying the composition of the CLC we can continuously tune the wavelength band of retroreflection across the visible spectrum and into the ultraviolet (UV) as well as infrared (IR) regimes, choose whether the CRSs reflect right- or left-handed circular polarization, and we can make them polymerizable, such that the CSRs are easily turned into solids after annealing, allowing easy manipulation and incorporation into diverse matrices. This opens for numerous innovative applications, from anti-counterfeiting and supply chain track-and-trace solutions, via human-invisible signage optimized for robots and AR device wayfinding, to the pixelation of structural color for generating non-spectral colors without absorption or indiscriminate scattering, and even enhanced-sensitivity disease testing. In my talk, I will briefly introduce the concept of CSRs and highlight their salient features, and then I will focus on our on-going efforts to solve important societally and industrially relevant problems by taking advantage of the opportunities offered by CSRs.

Disciplines :

Physics

Author, co-author :

LAGERWALL, Jan ; University of Luxembourg > Faculty of Science, Technology and Medicine (FSTM) > Department of Physics and Materials Science (DPHYMS)

External co-authors :

Language :

English

Title :

Cholesteric spherical reflectors as innovative optical elements with vast application potential

Publication date :

13 March 2024

Event name :

Emerging Liquid Crystal Technologies XIX

Event place :

San Francisco, Usa

Event date :

30-01-2024 => 31-01-2024

By request :

Yes

Audience :

International

Main work title :

Emerging Liquid Crystal Technologies XIX

Editor :

Chien, Liang-Chy

Publisher :

SPIE

ISBN/EAN :

978-1-5106-7074-7

Funders :

The Society of Photo-Optical Instrumentation Engineers (SPIE)

Funding text :

I am indebted to numerous collaborators who have helped develop our research in CSRs over the years; I would particularly like to mention Irena Drevensek-Olenik, Mathew Schwartz, Gabriele Lenzini, Holger Voos and Benny Mantin. I would also like to thank all my current and previous group members who worked with CSRs, advancing our understanding and demonstrating the potential of these peculiar photonic elements. Financial support from the University of Luxembourg Institute for Advanced Studies (AUDACITY project TRANSCEND), the Luxembourg National Research Fund FNR (grant references C20/MS/14771094 ECLIPSE, C21 MS 16325006 BIOFLICS, C17/MS/11688643 SSh, and PoC20/15299666/NOFAKES-PoC NOFAKES) and the European Research Council (project VALIDATE, Grant Code 862315) is gratefully acknowledged. For the purpose of open access, the authors have applied a Creative Commons Attribution 4.0 International (CC BY 4.0) license to any Author Accepted Manuscript version arising from this submission

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