The seemingly simple step of molding a cholesteric liquid crystal into spherical shape,yielding a Cholesteric Spherical Reflector(CSR),has profound optical consequences that open a range of opportunities for potential...The seemingly simple step of molding a cholesteric liquid crystal into spherical shape,yielding a Cholesteric Spherical Reflector(CSR),has profound optical consequences that open a range of opportunities for potentially transformative technologies.The chiral Bragg diffraction resulting from the helical self-assembly of cholesterics becomes omnidirectional in CSRs.This turns them into selective retroreflectors that are exceptionally easy to distinguish-regardless of background--by simple and low-cost machine vision,while at the same time they can be made largely imperceptible to human vision.This allows them to be distributed in human-populated environments,laid out in the form of QR-code-like markers that help robots and Augmented Reality(AR)devices to operate reliably,and to identify items in their surroundings.At the scale of individual CSRs,unpredictable features within each marker turn them into Physical Unclonable Functions(PUFs),of great value for secure authentication.Via the machines reading them,CSR markers can thus act as trustworthy yet unobtrusive links between the physical world(buildings,vehicles,packaging...).and its digital twin computer representation.This opens opportunities to address pressing challenges in logistics and supply chain management,recycling and the circular economy,sustainable construction of the built environment,and many other fields of individual,societal and commercial importance.展开更多
基金the Luxembourg National Research Fund(FNR),grant reference C20_MS_14771094(ECLIPSE)For the purpose of open access,the author has applied a Creative Commons Atribution 4.0 International(CC BY 4.0)license to any Author Accepted Manuscript version arising from this submission.Further financial support is gratefully acknowledged from the Office of Naval Research Global(Project LAB'RINTH)+1 种基金the Institute of Advanced Studies of the University of Luxembourg(project TRANSCEND)the European Research Council(ERC,Proof-of-C oncept project VALIDATE,Grant Code 862315).
文摘The seemingly simple step of molding a cholesteric liquid crystal into spherical shape,yielding a Cholesteric Spherical Reflector(CSR),has profound optical consequences that open a range of opportunities for potentially transformative technologies.The chiral Bragg diffraction resulting from the helical self-assembly of cholesterics becomes omnidirectional in CSRs.This turns them into selective retroreflectors that are exceptionally easy to distinguish-regardless of background--by simple and low-cost machine vision,while at the same time they can be made largely imperceptible to human vision.This allows them to be distributed in human-populated environments,laid out in the form of QR-code-like markers that help robots and Augmented Reality(AR)devices to operate reliably,and to identify items in their surroundings.At the scale of individual CSRs,unpredictable features within each marker turn them into Physical Unclonable Functions(PUFs),of great value for secure authentication.Via the machines reading them,CSR markers can thus act as trustworthy yet unobtrusive links between the physical world(buildings,vehicles,packaging...).and its digital twin computer representation.This opens opportunities to address pressing challenges in logistics and supply chain management,recycling and the circular economy,sustainable construction of the built environment,and many other fields of individual,societal and commercial importance.
