The strong optical chirality arising from certain synthetic metamaterials has important and widespread applications in polarization optics,stereochemistry and spintronics.However,these intrinsically chiral metamateria...The strong optical chirality arising from certain synthetic metamaterials has important and widespread applications in polarization optics,stereochemistry and spintronics.However,these intrinsically chiral metamaterials are restricted to a complicated three-dimensional(3D)geometry,which leads to significant fabrication challenges,particularly at visible wavelengths.Their planar two-dimensional(2D)counterparts are limited by symmetry considerations to operation at oblique angles(extrinsic chirality)and possess significantly weaker chiro-optical responses close to normal incidence.Here,we address the challenge of realizing strong intrinsic chirality from thin,planar dielectric nanostructures.Most notably,we experimentally achieve near-unity circular dichroism with~90%of the light with the chosen helicity being transmitted at a wavelength of 540 nm.This is the highest value demonstrated to date for any geometry in the visible spectrum.We interpret this result within the charge-current multipole expansion framework and show that the excitation of higher-order multipoles is responsible for the giant circular dichroism.These experimental results enable the realization of high-performance miniaturized chiro-optical components in a scalable manner at optical frequencies.展开更多
基金supported in part by the Air Force Office of Scientific Research(MURI,Grant Nos FA9550-14-1-0389 and FA9550-16-1-0156)support from King Abdullah University of Science and Technology under Award OSR-2016-CRG5-2995+3 种基金Harvard SEAS and A*STAR Singapore under the National Science Scholarship schemesupport from the Ministry of Science and Technology,Taiwan(Grant No.104-2917-I-564-058)supported by the National Research Foundation,Prime Minister’s Office,Singapore under its Competitive Research Program(CRP Award No.NRF-CRP15-2015-03)supported by the National Science Foundation under NSF Award No.1541959.CNS is a part of Harvard University.
文摘The strong optical chirality arising from certain synthetic metamaterials has important and widespread applications in polarization optics,stereochemistry and spintronics.However,these intrinsically chiral metamaterials are restricted to a complicated three-dimensional(3D)geometry,which leads to significant fabrication challenges,particularly at visible wavelengths.Their planar two-dimensional(2D)counterparts are limited by symmetry considerations to operation at oblique angles(extrinsic chirality)and possess significantly weaker chiro-optical responses close to normal incidence.Here,we address the challenge of realizing strong intrinsic chirality from thin,planar dielectric nanostructures.Most notably,we experimentally achieve near-unity circular dichroism with~90%of the light with the chosen helicity being transmitted at a wavelength of 540 nm.This is the highest value demonstrated to date for any geometry in the visible spectrum.We interpret this result within the charge-current multipole expansion framework and show that the excitation of higher-order multipoles is responsible for the giant circular dichroism.These experimental results enable the realization of high-performance miniaturized chiro-optical components in a scalable manner at optical frequencies.
