1
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Zhang G, Yallapragada VJ, Halperin T, Wagner A, Shemesh M, Upcher A, Pinkas I, McClelland HLO, Hawlena D, Palmer BA. Lizards exploit the changing optics of developing chromatophore cells to switch defensive colors during ontogeny. Proc Natl Acad Sci U S A 2023; 120:e2215193120. [PMID: 37104475 PMCID: PMC10161005 DOI: 10.1073/pnas.2215193120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023] Open
Abstract
Many animals undergo changes in functional colors during development, requiring the replacement of integument or pigment cells. A classic example of defensive color switching is found in hatchling lizards, which use conspicuous tail colors to deflect predator attacks away from vital organs. These tail colors usually fade to concealing colors during ontogeny. Here, we show that the ontogenetic blue-to-brown tail color change in Acanthodactylus beershebensis lizards results from the changing optical properties of single types of developing chromatophore cells. The blue tail colors of hatchlings are produced by incoherent scattering from premature guanine crystals in underdeveloped iridophore cells. Cryptic tail colors emerge during chromatophore maturation upon reorganization of the guanine crystals into a multilayer reflector concomitantly with pigment deposition in the xanthophores. Ontogenetic changes in adaptive colors can thus arise not via the exchange of different optical systems, but by harnessing the timing of natural chromatophore development. The incoherent scattering blue color here differs from the multilayer interference mechanism used in other blue-tailed lizards, indicating that a similar trait can be generated in at least two ways. This supports a phylogenetic analysis showing that conspicuous tail colors are prevalent in lizards and that they evolved convergently. Our results provide an explanation for why certain lizards lose their defensive colors during ontogeny and yield a hypothesis for the evolution of transiently functional adaptive colors.
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Affiliation(s)
- Gan Zhang
- Department of Chemistry, Ben-Gurion University of the Negev, Be'er Sheva 8410501, Israel
| | - Venkata Jayasurya Yallapragada
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Topaz Halperin
- Department of Ecology, Evolution and Behavior, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Department of Philosophy, The Hebrew University of Jerusalem, Jerusalem 9190501, Israel
| | - Avital Wagner
- Department of Chemistry, Ben-Gurion University of the Negev, Be'er Sheva 8410501, Israel
| | - Michal Shemesh
- Department of Ecology, Evolution and Behavior, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Alexander Upcher
- Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheva 8410501, Israel
| | - Iddo Pinkas
- Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Harry L O McClelland
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Parkville, VIC 3053, Australia
| | - Dror Hawlena
- Department of Ecology, Evolution and Behavior, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Benjamin A Palmer
- Department of Chemistry, Ben-Gurion University of the Negev, Be'er Sheva 8410501, Israel
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2
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Lemcoff T, Alus L, Haataja JS, Wagner A, Zhang G, Pavan MJ, Yallapragada VJ, Vignolini S, Oron D, Schertel L, Palmer BA. Brilliant whiteness in shrimp from ultra-thin layers of birefringent nanospheres. Nat Photonics 2023; 17:485-493. [PMID: 37287680 PMCID: PMC10241642 DOI: 10.1038/s41566-023-01182-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/24/2023] [Indexed: 06/09/2023]
Abstract
A fundamental question regarding light scattering is how whiteness, generated from multiple scattering, can be obtained from thin layers of materials. This challenge arises from the phenomenon of optical crowding, whereby, for scatterers packed with filling fractions higher than ~30%, reflectance is drastically reduced due to near-field coupling between the scatterers. Here we show that the extreme birefringence of isoxanthopterin nanospheres overcomes optical crowding effects, enabling multiple scattering and brilliant whiteness from ultra-thin chromatophore cells in shrimp. Strikingly, numerical simulations reveal that birefringence, originating from the spherulitic arrangement of isoxanthopterin molecules, enables intense broadband scattering almost up to the maximal packing for random spheres. This reduces the thickness of material required to produce brilliant whiteness, resulting in a photonic system that is more efficient than other biogenic or biomimetic white materials which operate in the lower refractive index medium of air. These results highlight the importance of birefringence as a structural variable to enhance the performance of such materials and could contribute to the design of biologically inspired replacements for artificial scatterers like titanium dioxide.
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Affiliation(s)
- Tali Lemcoff
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Lotem Alus
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Johannes S. Haataja
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Department of Applied Physics, Aalto University School of Science, Espoo, Finland
| | - Avital Wagner
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Gan Zhang
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Present Address: College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China
| | - Mariela J. Pavan
- Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | - Silvia Vignolini
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Dan Oron
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Lukas Schertel
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Department of Physics, University of Fribourg, Fribourg, Switzerland
| | - Benjamin A. Palmer
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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3
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Shavit K, Wagner A, Schertel L, Farstey V, Akkaynak D, Zhang G, Upcher A, Sagi A, Yallapragada VJ, Haataja J, Palmer BA. A tunable reflector enabling crustaceans to see but not be seen. Science 2023; 379:695-700. [PMID: 36795838 DOI: 10.1126/science.add4099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Many oceanic prey animals use transparent bodies to avoid detection. However, conspicuous eye pigments, required for vision, compromise the organisms' ability to remain unseen. We report the discovery of a reflector overlying the eye pigments in larval decapod crustaceans and show how it is tuned to render the organisms inconspicuous against the background. The ultracompact reflector is constructed from a photonic glass of crystalline isoxanthopterin nanospheres. The nanospheres' size and ordering are modulated to tune the reflectance from deep blue to yellow, enabling concealment in different habitats. The reflector may also function to enhance the acuity or sensitivity of the minute eyes by acting as an optical screen between photoreceptors. This multifunctional reflector offers inspiration for constructing tunable artificial photonic materials from biocompatible organic molecules.
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Affiliation(s)
- Keshet Shavit
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Avital Wagner
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Lukas Schertel
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.,Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Viviana Farstey
- The Interuniversity Institute for Marine Sciences, Eilat 8810302, Israel
| | - Derya Akkaynak
- The Interuniversity Institute for Marine Sciences, Eilat 8810302, Israel.,Hatter Department of Marine Technologies, University of Haifa, Haifa 3498838, Israel
| | - Gan Zhang
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Alexander Upcher
- Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheba 8410501, Israel
| | - Amir Sagi
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.,The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | | | - Johannes Haataja
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Benjamin A Palmer
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
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4
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Lubin G, Yaniv G, Kazes M, Ulku AC, Antolovic IM, Burri S, Bruschini C, Charbon E, Yallapragada VJ, Oron D. Resolving the Controversy in Biexciton Binding Energy of Cesium Lead Halide Perovskite Nanocrystals through Heralded Single-Particle Spectroscopy. ACS Nano 2021; 15:19581-19587. [PMID: 34846120 PMCID: PMC8717625 DOI: 10.1021/acsnano.1c06624] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Understanding exciton-exciton interaction in multiply excited nanocrystals is crucial to their utilization as functional materials. Yet, for lead halide perovskite nanocrystals, which are promising candidates for nanocrystal-based technologies, numerous contradicting values have been reported for the strength and sign of their exciton-exciton interaction. In this work, we unambiguously determine the biexciton binding energy in single cesium lead halide perovskite nanocrystals at room temperature. This is enabled by the recently introduced single-photon avalanche diode array spectrometer, capable of temporally isolating biexciton-exciton emission cascades while retaining spectral resolution. We demonstrate that CsPbBr3 nanocrystals feature an attractive exciton-exciton interaction, with a mean biexciton binding energy of 10 meV. For CsPbI3 nanocrystals, we observe a mean biexciton binding energy that is close to zero, and individual nanocrystals show either weakly attractive or weakly repulsive exciton-exciton interaction. We further show that, within ensembles of both materials, single-nanocrystal biexciton binding energies are correlated with the degree of charge-carrier confinement.
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Affiliation(s)
- Gur Lubin
- Department
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
| | - Gili Yaniv
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Miri Kazes
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Arin Can Ulku
- School
of Engineering, École polytechnique
fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Ivan Michel Antolovic
- School
of Engineering, École polytechnique
fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Samuel Burri
- School
of Engineering, École polytechnique
fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Claudio Bruschini
- School
of Engineering, École polytechnique
fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Edoardo Charbon
- School
of Engineering, École polytechnique
fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Venkata Jayasurya Yallapragada
- Department
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
- Department
of Physics, Indian Institute of Technology
Kanpur, Kanpur 208016, India
- (V.J.Y.)
| | - Dan Oron
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
- (D.O.)
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5
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Lubin G, Tenne R, Ulku AC, Antolovic IM, Burri S, Karg S, Yallapragada VJ, Bruschini C, Charbon E, Oron D. Heralded Spectroscopy Reveals Exciton-Exciton Correlations in Single Colloidal Quantum Dots. Nano Lett 2021; 21:6756-6763. [PMID: 34398604 PMCID: PMC8397400 DOI: 10.1021/acs.nanolett.1c01291] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Multiply excited states in semiconductor quantum dots feature intriguing physics and play a crucial role in nanocrystal-based technologies. While photoluminescence provides a natural probe to investigate these states, room-temperature single-particle spectroscopy of their emission has proved elusive due to the temporal and spectral overlap with emission from the singly excited and charged states. Here, we introduce biexciton heralded spectroscopy enabled by a single-photon avalanche diode array based spectrometer. This allows us to directly observe biexciton-exciton emission cascades and measure the biexciton binding energy of single quantum dots at room temperature, even though it is well below the scale of thermal broadening and spectral diffusion. Furthermore, we uncover correlations hitherto masked in ensembles of the biexciton binding energy with both charge-carrier confinement and fluctuations of the local electrostatic potential. Heralded spectroscopy has the potential of greatly extending our understanding of charge-carrier dynamics in multielectron systems and of parallelization of quantum optics protocols.
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Affiliation(s)
- Gur Lubin
- Deptartment
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
| | - Ron Tenne
- Deptartment
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
- Department
of Physics and Center for Applied Photonics, University of Konstanz, Konstanz D-78457, Germany
| | - Arin Can Ulku
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Ivan Michel Antolovic
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Samuel Burri
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Sean Karg
- Deptartment
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
| | | | - Claudio Bruschini
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Edoardo Charbon
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Dan Oron
- Deptartment
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
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6
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Beck LM, Yallapragada VJ, Upcher A, Palmer BA, Addadi L, Oron D. Measuring the optical properties of nanoscale biogenic spherulites. Opt Express 2021; 29:20863-20871. [PMID: 34266166 DOI: 10.1364/oe.430376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 05/30/2021] [Indexed: 06/13/2023]
Abstract
Recent studies of optical reflectors as part of the vision apparatus in the eyes of decapod crustaceans revealed assemblies of nanoscale spherulites - spherical core-shell nanoparticles with radial birefringence. Simulations performed on the system highlighted the advantages of optical anisotropy in enhancing the functionality of these structures. So far, calculations of the nanoparticle optical properties have relied on refractive indices obtained using ab-initio calculations. Here we describe a direct measurement of the tangential refractive index of the spherulites, which corresponds to the in-plane refractive index of crystalline isoxanthopterin nanoplatelets. We utilize measurements of scattering spectra of individual spherulites and determine the refractive index by analyzing the spectral signatures of scattering resonances. Our measurements yield a median tangential refractive index of 1.88, which is in reasonable agreement with theoretical predictions. Furthermore, our results indicate that the optical properties of small spherulite assemblies are largely determined by the tangential index.
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7
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Schiffmann N, Wormser EM, Brumfeld V, Addadi Y, Pinkas I, Yallapragada VJ, Aflalo ED, Sagi A, Palmer BA, Weiner S, Addadi L. Characterization and possible function of an enigmatic reflector in the eye of the shrimp Litopenaeus vannamei. Faraday Discuss 2020; 223:278-294. [PMID: 32748932 DOI: 10.1039/d0fd00044b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Reflective assemblies of high refractive index organic crystals are used to produce striking optical phenomena in organisms based on light reflection and scattering. In aquatic animals, organic crystal-based reflectors are used both for image-formation and to increase photon capture. Here we report the characterization of a poorly-documented reflector in the eye of the shrimp L. vannamei lying 150 μm below the retina, which we term the proximal reflective layer (PR-layer). The PR-layer is made from a dense but disordered array of polycrystalline isoxanthopterin nanoparticles, similar to those recently reported in the tapetum of the same animal. Each spherical nanoparticle is composed of numerous isoxanthopterin single crystal plates arranged in concentric lamellae around an aqueous core. The highly reflective plate faces of the crystals are all aligned tangentially to the particle surface with the optical axes projecting radially outwards, forming a birefringent spherulite which efficiently scatters light. The nanoparticle assemblies form a broadband reflective sheath around the screening pigments of the eye, resulting in pronounced eye-shine when the animal is viewed from a dorsal-posterior direction, rendering the eye pigments inconspicuous. We assess possible functions of the PR-layer and conclude that it likely functions as a camouflage device to conceal the dark eye pigments in an otherwise largely transparent animal.
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Affiliation(s)
- Nathan Schiffmann
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel.
| | - Eyal Merary Wormser
- Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | - Vlad Brumfeld
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Yoseph Addadi
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Iddo Pinkas
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | | | - Eliahu D Aflalo
- Department of Life Sciences, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel and Department of Life Sciences, Achva Academic College, Arugot, Israel
| | - Amir Sagi
- Department of Life Sciences, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel and The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | - Benjamin A Palmer
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel.
| | - Steve Weiner
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel.
| | - Lia Addadi
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel.
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8
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Benjamin E, Yallapragada VJ, Amgar D, Yang G, Tenne R, Oron D. Temperature Dependence of Excitonic and Biexcitonic Decay Rates in Colloidal Nanoplatelets by Time-Gated Photon Correlation. J Phys Chem Lett 2020; 11:6513-6518. [PMID: 32693606 PMCID: PMC7458474 DOI: 10.1021/acs.jpclett.0c01628] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/22/2020] [Indexed: 05/20/2023]
Abstract
Excitons in colloidal semiconductor nanoplatelets (NPLs) are weakly confined in the lateral dimensions. This results in significantly smaller Auger rates and, consequently, larger biexciton quantum yields, when compared to spherical quantum dots (QDs). Here we report a study of the temperature dependence of the biexciton Auger rate in individual CdSe/CdS core-shell NPLs, through the measurement of time-gated second-order photon correlations in the photoluminescence. We also utilize this method to directly estimate the single-exciton radiative rate. We find that whereas the radiative lifetime of NPLs increases with temperature, the Auger lifetime is almost temperature-independent. Our findings suggest that Auger recombination in NPLs is qualitatively similar to that of semiconductor quantum wells. Time-gated photon correlation measurements offer the unique ability to study multiphoton emission events, while excluding effects of competing fast processes, and can provide significant insight into the photophysics of a variety of nanocrystal multiphoton emitters.
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9
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Palmer BA, Yallapragada VJ, Schiffmann N, Wormser EM, Elad N, Aflalo ED, Sagi A, Weiner S, Addadi L, Oron D. A highly reflective biogenic photonic material from core-shell birefringent nanoparticles. Nat Nanotechnol 2020; 15:138-144. [PMID: 31932761 DOI: 10.1038/s41565-019-0609-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 12/02/2019] [Indexed: 05/24/2023]
Abstract
Spectacular natural optical phenomena are produced by highly reflective assemblies of organic crystals. Here we show how the tapetum reflector in a shrimp eye is constructed from arrays of spherical isoxanthopterin nanoparticles and relate the particle properties to their optical function. The nanoparticles are composed of single-crystal isoxanthopterin nanoplates arranged in concentric lamellae around a hollow core. The spherulitic birefringence of the nanoparticles, which originates from the radial alignment of the plates, results in a significant enhancement of the back-scattering. This enables the organism to maximize the reflectivity of the ultrathin tapetum, which functions to increase the eye's sensitivity and preserve visual acuity. The particle size, core/shell ratio and packing are also controlled to optimize the intensity and spectral properties of the tapetum back-scattering. This system offers inspiration for the design of photonic crystals constructed from spherically symmetric birefringent particles for use in ultrathin reflectors and as non-iridescent pigments.
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Affiliation(s)
- Benjamin A Palmer
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
| | | | - Nathan Schiffmann
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Eyal Merary Wormser
- Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Nadav Elad
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Eliahu D Aflalo
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Department of Life Sciences, Achva Academic College, Arugot, Israel
| | - Amir Sagi
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Steve Weiner
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Lia Addadi
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Dan Oron
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel.
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10
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Yallapragada VJ, Oron D. Optical properties of spherulite opals. Opt Lett 2019; 44:5860-5863. [PMID: 31774798 DOI: 10.1364/ol.44.005860] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/05/2019] [Indexed: 06/10/2023]
Abstract
Spherulites are birefringent structures with spherical symmetry, typically observed in crystallized polymers. We compute the band structure of opals made of close-packed assemblies of highly birefringent spherulites. We demonstrate that spherulitic birefringence of constituent spheres does not affect the symmetries of an opal, yet significantly affects the dispersion of eigenmodes, leading to new pseudogaps in sections of the band structure and, consequently, enhanced reflectivity.
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11
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Yallapragada VJ, Mulay GL, Rao CN, Ravishankar AP, Achanta VG. Direct measurement of the Goos-Hänchen shift using a scanning quadrant detector and a polarization maintaining fiber. Rev Sci Instrum 2016; 87:103109. [PMID: 27802693 DOI: 10.1063/1.4964730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
High precision measurements of optical beam shifts are important in various fields including sensing, atomic force microscopy, and measuring beam shifts at interfaces. Sub-micron shifts are generally measured by indirect techniques such as weak measurements. We demonstrate a straightforward and robust measurement scheme for the shift, based on a scanning quadrant photodiode (QPD) that is biased using a low noise electronic circuit. The shift is measured with respect to a reference beam that is co-propagating with the signal beam. Thus, the shift of the signal beam is readout directly as the difference between the x-intercepts of the QPD scan plot of the signal and reference beams versus the position of the detector. To measure the beam shift, we use polarization multiplexing scheme where the p-polarized signal and s-polarized reference beams are modulated at two different frequencies and co-launched into a polarization-maintaining fiber. Both the signal and reference beam positions are readout by two lock-in amplifiers simultaneously. In order to demonstrate the utility of this method, we perform a direct measurement of Goos-Hänchen shift of a beam that is reflected from a plane gold surface. Accuracy of 150 nm is achieved using this technique.
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Affiliation(s)
| | - Gajendra L Mulay
- Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Ch N Rao
- Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Ajith P Ravishankar
- Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Venu Gopal Achanta
- Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
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12
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Yallapragada VJ, Ravishankar AP, Mulay GL, Agarwal GS, Achanta VG. Erratum: Observation of giant Goos-Hänchen and angular shifts at designed metasurfaces. Sci Rep 2016; 6:23835. [PMID: 27072021 PMCID: PMC4829899 DOI: 10.1038/srep23835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Yallapragada VJ, Ravishankar AP, Mulay GL, Agarwal GS, Achanta VG. Observation of giant Goos-Hänchen and angular shifts at designed metasurfaces. Sci Rep 2016; 6:19319. [PMID: 26758471 PMCID: PMC4725830 DOI: 10.1038/srep19319] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/07/2015] [Indexed: 11/24/2022] Open
Abstract
Metasurfaces with sub-wavelength features are useful in modulating the phase, amplitude or polarization of electromagnetic fields. While several applications are reported for light manipulation and control, the sharp phase changes would be useful in enhancing the beam shifts at reflection from a metasurface. In designed periodic patterns on metal film, at surface plasmon resonance, we demonstrate Goos-Hanchen shift of the order of 70 times the incident wavelength and the angular shifts of several hundred microradians. We have designed the patterns using rigorous coupled wave analysis (RCWA) together with S-matrices and have used a complete vector theory to calculate the shifts as well as demonstrate a versatile experimental setup to directly measure the shifts. The giant shifts demonstrated could prove to be useful in enhancing the sensitivity of experiments ranging from atomic force microscopy to gravitational wave detection.
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Affiliation(s)
| | - Ajith P Ravishankar
- DCMP &MS, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 INDIA
| | - Gajendra L Mulay
- DCMP &MS, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 INDIA
| | - Girish S Agarwal
- Department of Physics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Venu Gopal Achanta
- DCMP &MS, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 INDIA
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Abstract
We present the first calculation of the Goos-Hänchen shifts in the context of the nonlinear generation of fields. We specifically concentrate on shifts of second harmonic generated at metallic surfaces. At metallic surfaces the second harmonic primarily arises from discontinuities of the field at surfaces which not only result in large harmonic generation but also in significant Goos-Hänchen shifts of the generated second harmonic. Our results can be extended to other shifts like angular shifts and Fedorov-Imbert shifts.
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Affiliation(s)
- V J Yallapragada
- Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
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