Circular dichroism(CD)spectroscopy,widely used for chiral sensing,has been limited by the detection sensitivity.Enhancing optical chirality in the light fields interacting with chiral molecules is crucial for achievin...Circular dichroism(CD)spectroscopy,widely used for chiral sensing,has been limited by the detection sensitivity.Enhancing optical chirality in the light fields interacting with chiral molecules is crucial for achieving ultrasensitive chiral detection.Here,we present a new paradigm for ultrasensitive chiral detection by creating accessible chiral hotspots using a toroidal dipole Fabry–Perot bound state in the continuum(TD FP-BIC)metasurface.BIC resonance is achieved by controlling the coupling between the TD resonance and its multilayer reflector-induced perfect mirror image.This method enables unprecedented local maximum and average optical chirality enhancements of up to 6×10^(4)-fold and 2×10^(3)-fold,respectively,within non-structured regions,resulting in an 866-fold increase in CD signals compared to chiral molecules alone without nanostructures.Our results pave the way for enhanced light–matter interactions and ultrasensitive enantiomeric operation.展开更多
基金National Key Research and Development Program of China(2023YFF0615604)National Natural Science Foundation of China(62192770,62305252,62205246,62475192,61925504,62020106009,62192771)+3 种基金Science and Technology Commission of Shanghai Municipality(21JC1406100,22ZR1432400)Shanghai Municipal Science and Technology Major Project(2021SHZDZX0100)Shanghai Pilot Program for Basic ResearchFundamental Research Funds for the Central Universities。
文摘Circular dichroism(CD)spectroscopy,widely used for chiral sensing,has been limited by the detection sensitivity.Enhancing optical chirality in the light fields interacting with chiral molecules is crucial for achieving ultrasensitive chiral detection.Here,we present a new paradigm for ultrasensitive chiral detection by creating accessible chiral hotspots using a toroidal dipole Fabry–Perot bound state in the continuum(TD FP-BIC)metasurface.BIC resonance is achieved by controlling the coupling between the TD resonance and its multilayer reflector-induced perfect mirror image.This method enables unprecedented local maximum and average optical chirality enhancements of up to 6×10^(4)-fold and 2×10^(3)-fold,respectively,within non-structured regions,resulting in an 866-fold increase in CD signals compared to chiral molecules alone without nanostructures.Our results pave the way for enhanced light–matter interactions and ultrasensitive enantiomeric operation.
