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| Open AccessIntrinsic dichroism in amorphous and crystalline solids with helical light
Differential absorption of polarized light, called dichroism, does not exist in amorphous solids due to the disordered arrangements of atoms. Here, the authors demonstrate that dichroism is intrinsic to all solids and can be controlled using helical light beams carrying orbital angular momentum.
- Ashish Jain
- , Jean-Luc Bégin
- & Ravi Bhardwaj
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| Open AccessTheory predicts 2D chiral polaritons based on achiral Fabry–Pérot cavities using apparent circular dichroism
2D chiral polaritons are light-matter states with select angular momentum holding technological promise. Here, the authors present the theory of such states, and propose their realisation based on a phenomenon called “apparent circular dichroism”.
- Andrew H. Salij
- , Randall H. Goldsmith
- & Roel Tempelaar
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| Open AccessUncovering the chiral bias of meteoritic isovaline through asymmetric photochemistry
Excess of l-amino acids in meteorites suggests an extraterrestrial origin of biomolecular homochirality, which may stem from chiral light-matter interactions. Here the authors support this hypothesis with asymmetric photolysis experiments on racemic isovaline films, showing that circularly polarized starlight can produce l-enantiomeric excesses that can be amplified during parent bodies’ alteration.
- Jana Bocková
- , Nykola C. Jones
- & Cornelia Meinert
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| Open AccessTheoretical and experimental analysis of circularly polarized luminescence spectrophotometers for artifact-free measurements using a single CCD camera
The authors present an artifact-free circularly polarized luminescence spectrophotometer using a single camera and two polarization encoding paths. The spectra are measured in a few seconds without the need of calibration by inverting the role of the paths.
- Bruno Baguenard
- , Amina Bensalah-Ledoux
- & Stéphan Guy
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| Open AccessDual-comb optical activity spectroscopy for the analysis of vibrational optical activity induced by external magnetic field
Dual-comb spectroscopy was first applied to the measurement of magnetic optical activity spectroscopy, realizing Doppler-limited gas-phase molecular analysis, and was further extended to the rapid measurement of liquid-phase chiroptical activity.
- Daowang Peng
- , Chenglin Gu
- & Wenxue Li
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| Open AccessAmino acid gas phase circular dichroism and implications for the origin of biomolecular asymmetry
Chiroptical properties of amino acids are challenging to investigate in the gas phase due to the low vapor pressure of these molecules. Here the authors succeed in measuring circular dichroism active transitions and anisotropies in the ultraviolet range for several gas-phase amino acids, shedding light on the interactions between molecules and circularly polarized light that lead to chiral symmetry breaking.
- Cornelia Meinert
- , Adrien D. Garcia
- & Uwe J. Meierhenrich
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| Open AccessMapping the broadband circular dichroism of copolymer films with supramolecular chirality in time and space
Time-resolved circular dichroism spectra can reveal changes in chirality on ultrashort time scales, but achieving sub-picosecond time resolution is still a challenge. Here the authors demonstrate 100-femtosecond time-resolved CD mapping of polyfluorene copolymer thin films, revealing a supramolecular origin of their chiroptical response.
- Marius Morgenroth
- , Mirko Scholz
- & Thomas Lenzer
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| Open AccessOptical deciphering of multinary chiral compound mixtures through organic reaction based chemometric chirality sensing
The stereoselective analysis of mixtures of chiral compounds typically requires time-consuming chromatography. Here, the authors combine reaction based chiroptical sensing and chemometric tools to directly determine the absolute configuration, enantiomeric composition and concentration of convoluted samples without physical separation.
- Diandra S. Hassan
- & Christian Wolf
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| Open AccessNatural optical activity as the origin of the large chiroptical properties in π-conjugated polymer thin films
Polymer thin films that emit and absorb circularly polarised light are promising in achieving important technological advances, but the origin of the large chiroptical effects in such films has remained elusive. Here the authors demonstrate that in non-aligned polymer thin films, large chiroptical effects are caused by magneto-electric coupling, not structural chirality as previously assumed.
- Jessica Wade
- , James N. Hilfiker
- & Matthew J. Fuchter
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| Open AccessChiroptical spectroscopy of a freely diffusing single nanoparticle
Chirality of nanostructures may be determined by ensemble measurements in solution or on single immobilized nanoparticles, with loss of detail or interference from the substrate. Here the authors demonstrate that circular differential scattering intensity spectra of freely diffusing single nanoparticles provide chiroptical spectra which reflect their intrinsic chirality.
- Johannes Sachs
- , Jan-Philipp Günther
- & Peer Fischer
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| Open AccessExploiting racemism enhanced organic room-temperature phosphorescence to demonstrate Wallach’s rule in the lighting chiral chromophores
Room temperature phosphorescence (RTP) is a topic which is currently widely studied, but a study on the correlation between types of molecular solid and RTP properties is lacking. Here the authors show that RTP is enhanced in the racemic form of axial chiral molecules due to its denser R- and S- cross packing arrangement.
- Xiugang Wu
- , Chun-Ying Huang
- & Pi-Tai Chou
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| Open AccessMethionine in a protein hydrophobic core drives tight interactions required for assembly of spider silk
Spider silk is of interest in material science research. Here the authors show that the tight binding of a spider silk protein domain relies on the amino acid methionine, which is abundant in the domain core where it facilitates dynamic shape adaption of the binding interface.
- Julia C. Heiby
- , Benedikt Goretzki
- & Hannes Neuweiler
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| Open AccessUltrafast long-range spin-funneling in solution-processed Ruddlesden–Popper halide perovskites
Spin-information transport or transfer is essential for spintronics applications and often relies on high purity and quality materials. Here, the authors report on the defect-tolerant solution-processed Ruddlesden–Popper halide perovskites, where a spin propagation length of 600 nm was achieved via spin funneling.
- David Giovanni
- , Jia Wei Melvin Lim
- & Tze Chien Sum
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| Open AccessClick chemistry enables quantitative chiroptical sensing of chiral compounds in protic media and complex mixtures
Chiroptical sensing in complex mixtures remains a challenging task. Here, the authors report an efficient coumarin probe for chiroptical click chirality sensing of absolute configuration, concentration and enantiomeric excess of several compound classes. The method can be directly applied to crude asymmetric reaction mixtures.
- F. Yushra Thanzeel
- , Kaluvu Balaraman
- & Christian Wolf
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| Open AccessReal-time determination of enantiomeric and isomeric content using photoelectron elliptical dichroism
The analysis of chiral chemical mixtures is crucial for many applications. Here, the authors perform real-time analysis of samples by ionizing them with elliptically polarized femtosecond laser pulses and detecting the angular distributions of the photoelectrons.
- A. Comby
- , E. Bloch
- & Y. Mairesse
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| Open AccessIn situ monitoring of molecular aggregation using circular dichroism
Molecular aggregation is a widespread and important process in physiological metabolism, but details regarding conformational changes during the process are hard to probe. Here, the authors use circular dichroism to monitor in-situ the conformational changes occurring during molecular aggregation.
- Haoke Zhang
- , Xiaoyan Zheng
- & Ben Zhong Tang
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| Open AccessTwo-step self-assembly of a spider silk molecular clamp
Molecular details that underlie mechanical properties of spider silk are of great interest to material scientists. Here, the authors report a previously unknown three-state mechanism of folding and an expanded structure of a spider silk protein that may contribute to elasticity of spider silk.
- Charlotte Rat
- , Julia C. Heiby
- & Hannes Neuweiler
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| Open AccessIntracellular localization of nanoparticle dimers by chirality reversal
The ability to spectroscopically pinpoint whether nanoparticles are located inside or outside of cells represents an overarching need in biology and medicine. Here, the authors show that the chirality of DNA-bridged particle dimers reverses when they cross the cell membrane, providing a real-time chiroptical signature of their intra- or extracellular location.
- Maozhong Sun
- , Liguang Xu
- & Chuanlai Xu
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| Open AccessExperimental determination of excitonic band structures of single-walled carbon nanotubes using circular dichroism spectra
The experimental determination of band structure of single wall carbon nanotubes (SWCNTs) is a challenging task, and often must be theoretically predicted. Here, the authors separate SWCNTs in high purity and experimentally determine their excitonic band structures using circular dichroism spectra.
- Xiaojun Wei
- , Takeshi Tanaka
- & Hiromichi Kataura
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| Open AccessAssembled molecular face-rotating polyhedra to transfer chirality from two to three dimensions
Protein subunits on the capsids of icosahedral viruses can form patterns with rotational symmetry, which are difficult to recreate in the laboratory. Here the authors report a strategy to construct 3D chiral polyhedra with rotational faces from 2D chiral truxene-based units through dynamic covalent chemistry.
- Xinchang Wang
- , Yu Wang
- & Xiaoyu Cao
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| Open AccessCircularly polarized light detection with hot electrons in chiral plasmonic metamaterials
Analysis and detection of circularly polarized light involves the use of multiple optical elements. Here, the authors demonstrate an ultracompact circularly polarized light detector using chiral plasmonic metamaterials with hot electron injection, realizing its implementation on an integrated photonic platform.
- Wei Li
- , Zachary J. Coppens
- & Jason Valentine
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| Open AccessChirality transfer from gold nanocluster to adsorbate evidenced by vibrational circular dichroism
The transfer of chirality from surfaces to molecular species may have implications in areas from the origin of homochirality to heterogeneous catalysis. Here, the authors show that a chiral gold cluster can transfer its inherent chirality to adsorbed, achiral molecules, causing them to adopt chiral conformations.
- Igor Dolamic
- , Birte Varnholt
- & Thomas Bürgi
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Triple-helical nanowires by tomographic rotatory growth for chiral photonics
Three-dimensional helical chiral metamaterials are required for nanophotonics but lack of full rotational symmetry has limited their use. Here, Esposito et al. combine chirality and isotropy, fabricating intertwined helical nanowires with 37% broadband circular dichroism with a high signal to noise ratio.
- Marco Esposito
- , Vittorianna Tasco
- & Adriana Passaseo
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Towards enabling femtosecond helicity-dependent spectroscopy with high-harmonic sources
High-harmonic generation is now capable of delivering high-energy X-ray pulses with short duration, but achieving elliptical polarization remains challenging. Here, Lambert et al. use a cross-polarized two-colour laser field to produce elliptically polarized X-rays and measure magnetic circular dichroism in nickel.
- G. Lambert
- , B. Vodungbo
- & M. Fajardo
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Angular momentum-induced circular dichroism in non-chiral nanostructures
The differential absorption of left and right handed light, circular dichroism, is typically observed only in chiral objects. Here, the authors demonstrate that giant circular dichroism can be induced in non-chiral objects when the left and right handed circularly polarized modes used are vortex beams.
- Xavier Zambrana-Puyalto
- , Xavier Vidal
- & Gabriel Molina-Terriza
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Determining the polarization state of an extreme ultraviolet free-electron laser beam using atomic circular dichroism
Intense extreme UV and X-ray coherent sources are set to revolutionize numerous research areas, yet characterization of their polarization remains elusive. Here, Mazza et al.measure the polarization state of circularly polarized extreme UV light from a free-electron laser using circular dichroism.
- T. Mazza
- , M. Ilchen
- & M. Meyer
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Quantitative characterization of nanoscale polycrystalline magnets with electron magnetic circular dichroism
Electron magnetic circular dichroism gives element-selective information on spin and orbital magnetic moments, but its low intensity has limited its use for nanoscale studies. Using a statistical analysis method, Muto et al.show that this can be overcome with nanometre-sized electron beams.
- Shunsuke Muto
- , Ján Rusz
- & Claus M. Schneider
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| Open AccessChiral plasmonic DNA nanostructures with switchable circular dichroism
Plasmonic resonances in nanoparticle helices arranged by the DNA origami method can give rise to strong circular dichroism at visible wavelengths. Schreiber et al. show that aligning and then toggling the orientation of such nanoparticle helices enables reversible switching of the dichroic response.
- Robert Schreiber
- , Ngoc Luong
- & Tim Liedl
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| Open AccessValley-selective circular dichroism of monolayer molybdenum disulphide
The monolayer transition-metal dichalcogenide molybdenum disulphide has recently attracted attention owing to its distinctive electronic properties. Cao and co-workers present numerical evidence suggesting that circularly polarized light can preferentially excite a single valley in the band structure of this system.
- Ting Cao
- , Gang Wang
- & Ji Feng