A tunable reflector enabling crustaceans to see but not be seen

Shavit, Keshet; Wagner, Avital; Schertel, Lukas; Farstey, Viviana; Akkaynak, Derya; Zhang, Gan; Upcher, Alexander; Sagi, Amir; Yallapragada, Venkata Jayasurya; Haataja, Johannes S.; Palmer, Benjamin A.

doi:10.1126/science.add4099

Cited by 22 publications

(22 citation statements)

References 47 publications

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“…This can be coupled with an evaluation of the respective structure fac-tor via, reconstruction, scattering or simulations, and then allow theoretical studies of the optical properties. [51][52][53][54] Since measurements in the UV-vis, as well as the IR-range, can be performed locally, this will allow efficient screening of optimized colloidal materials for, for example, radiative cooling applications. [55][56][57] In a more general sense, obtaining large data sets is becoming increasingly important.…”

Section: Discussionmentioning

confidence: 99%

Microspectroscopy on Thin Films of Colloidal Mixture Gradients for Data‐Driven Optimization of Optical Properties

Schöttle

Theis

Lauster

et al. 2023

Advanced Optical Materials

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Thin films comprising mixtures of different colloids provide a simple approach to materials with tunable optical properties. However, the prediction of UV–vis spectra for different compositions in colloidal crystals and glasses is difficult. The degree of disorder, for example, determines whether the optical response is dominated by incoherent scattering, coherent scattering, or Bragg diffraction. Both the volume ratio, as well as the morphology of the individual constituents, influence the properties of the ensemble, which necessitates extensive screening procedures. Here, a method for expediting such a screening approach by means of gradient colloidal crystals and glasses is shown. Continuous composition gradients, combined with local microspectroscopy, allow for the characterization of the entire composition range with high reproducibility, thereby reducing the experimental effort. This is shown for a system of spherical polymer particles with different radii. An optimum of the scattering efficiency in the visible wavelength range is shown close to the order/disorder transition at the edge of the composition range. The high‐throughput screening method presented here can generate large data sets that may contribute to machine‐learning‐enabled optimization of self‐assembled optical materials.

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Section: Discussionmentioning

confidence: 99%

Microspectroscopy on Thin Films of Colloidal Mixture Gradients for Data‐Driven Optimization of Optical Properties

Schöttle

Theis

Lauster

et al. 2023

Advanced Optical Materials

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show abstract

“…[ 25–28 ] Similarly, transparent pelagic creatures demonstrate natural camouflage, merging seamlessly with their environment as a protective mechanism against predators. [ 29 ] Such fascinating natural phenomena have inspired the creation of transparent anti‐counterfeiting systems. These systems camouflage information within their environment and selectively reveal it under specific external stimuli, offering an intuitive means to regulate information display.…”

Section: Introductionmentioning

confidence: 99%

Bio‐Inspired Cholesteric Phase Cellulose Composite with Thermochromic and Circularly Polarized Structural Color for Multilevel Encryption

Wen,

Zhang,

et al. 2023

Adv Funct Materials

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The escalating need for enhanced cryptographic security necessitates the development of advanced materials designed for the secure storage and transmission of information. Drawing inspiration from the unique color‐altering and polarizing capabilities of beetles, this work develops a transparent, thermochromic, and circularly polarized cholesteric phase cellulose composite (CPCC). This is achieved by integrating self‐assembled hydroxypropyl cellulose with cholesteric liquid crystal (CLC) structure in tandem with a crosslinked poly(N‐isopropyl acrylamide) (PNIPAM) network. The crosslinking density impacts the response degree of thermochromism, which can be regulated by modifying the UV exposure time during PNIPAM production. The CLC structure in CPCC uniquely results in reflected right circularly polarized light. When coupled with waveplates, this mechanism inverts the rotation direction of the reflected light, creating orthogonal structural colors of different brightness levels under left and right circularly polarized light. The excellent transparency of CPCC facilitates seamless integration with the environment, offering optimal camouflage. Sophisticated techniques, such as color coding and Morse coding, can further be incorporated within the CPCC to increase encryption security and the complexity of decryption. Collectively, the CPCC's transparency, thermochromism, and chirality present significant potential in the design and development of materials for high‐security information encryption, contributing valuable insights to the field.

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“…9,10 Some evidence in biological systems suggests that the combined mechanisms can create colors and optical properties unachievable by either mechanism alone. 11,12…”

Section: Introductionmentioning

confidence: 99%

“…9,10 Some evidence in biological systems suggests that the combined mechanisms can create colors and optical properties unachievable by either mechanism alone. 11,12 In day-to-day life, we create vivid non-iridescent color by starting with a white base and adding pigment. The white base scatters strongly across wavelengths, and diffusely reflects most of the light incident upon it.…”

Section: Introductionmentioning

confidence: 99%