Magnesium for Transient Photonics

Farinha, Thomas G.; Gong, Chen; Benson, Zackery A.; Leite, Marina S.

doi:10.1021/acsphotonics.8b01299

Cited by 18 publications

(28 citation statements)

References 46 publications

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“…241,243,249,250 Various mechanisms are employed to tune the optical system response such as a change in scatterer size or orientation, a change in the optical properties of the local environment of optical elements, and material phase transitions as summarized in Figure 4. 212,241,247,[251][252][253][254][255][256][257][258][259][260]…”

Section: Tunable Structural Colorsmentioning

confidence: 99%

Nanophotonic Structural Colors

et al. 2020

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Structural colors traditionally refer to colors arising from the interaction of light with structures with periodicities on the order of the wavelength. Recently, the definition has been broadened to include colors arising from individual resonators that can be subwavelength in dimension, e.g., plasmonic and dielectric nanoantennas. For instance, diverse metallic and dielectric nanostructure designs have been utilized to generate structural colors based on various physical phenomena, such as localized surface plasmon resonances (LSPRs), Mie resonances, thin-film Fabry-Pérot interference, and Rayleigh-Wood diffraction anomalies from 2D periodic lattices and photonic crystals. Here, we provide our perspective of the key application areas where structural colors really shine, and other areas where more work is needed. We review major classes of materials and structures employed to generate structural coloration and highlight the main physical resonances involved.

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Section: Tunable Structural Colorsmentioning

confidence: 99%

Nanophotonic Structural Colors

et al. 2020

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“…One of the most notable is based on the Tamm plasmon polaritons supported by a thin metal film on a multi-layer Bragg reflector stack [ 29 , 30 , 31 , 32 , 33 ]. Other useful materials include so-called black metals or plasmon super absorbers [ 33 , 34 , 35 , 36 , 37 ], which are comprised of a metal ground plate and a thin overlaying semiconductor film [ 28 , 36 , 38 ]. Absorber design can be optimized for reduced reflectivity and transmittance using the aforementioned optical impedance matching method [ 28 ], which is particularly promising when the refractive index

(where

is the permittivity) of the actual thin film is well known.…”

Section: Introductionmentioning

confidence: 99%

Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals

Kumagai

Balčytis

et al. 2020

Micromachines

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Lithography-free black metals composed of a nano-layered stack of materials are attractive not only due to their optical properties but also by virtue of fabrication simplicity and the cost reduction of devices based on such structures. We demonstrate multi-layer black metal layered structures with engineered electromagnetic absorption in the mid-infrared (MIR) wavelength range. Characterization of thin SiO2 and Si films sandwiched between two Au layers by way of experimental electromagnetic radiation absorption and thermal radiation emission measurements as well as finite difference time domain (FDTD) numerical simulations is presented. Comparison of experimental and simulation data derived optical properties of multi-layer black metals provide guidelines for absorber/emitter structure design and potential applications. In addition, relatively simple lithography-free multi-layer structures are shown to exhibit absorber/emitter performance that is on par with what is reported in the literature for considerably more elaborate nano/micro-scale patterned metasurfaces.

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“…Finally, we show that these materials can be used for physical encryption and readout based on the gaseous H 2 in the environment. Previously, Mg nanostructures have been used for similar types of encryption schemes due to its large optical change with H 2 . ,, In these works, e-beam lithography was used to create small and intricate encryption images. In our example, we work with thin film effects to make a macroscopic encryption scheme without the need for submicron nanostructuring.…”

Section: Resultsmentioning

confidence: 99%

In Situ Optical and Stress Characterization of Alloyed Pd_xAu_1–xHydrides

Palm

Murray

McClure

et al. 2019

ACS Appl. Mater. Interfaces

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Pd x Au1–x alloys have recently shown great promise for next-generation optical hydrogen sensors due to their increased chemical durability while their optical sensitivity to small amounts of hydrogen gas is maintained. However, the correlation between chemical composition and the dynamic optical behavior upon hydrogenation/dehydrogenation is currently not well understood. A complete understanding of this relation is necessary to optimize future sensors and nanophotonic devices. Here, we quantify the dynamic optical, chemical, and mechanical properties of thin film Pd x Au1–x alloys as they are exposed to H2 by combining in situ ellipsometry with gravimetric and stress measurements. We demonstrate the dynamic optical property dependence of the film upon hydrogenation and directly correlate it with the hydrogen content up to a maximum of 7 bar of H2. With this measurement, we find that the thin films exhibit their strongest optical sensitivity to H2 in the near-infrared. We also discover higher hydrogen-loading amounts as compared to previous measurements for alloys with low atomic percent Pd. Specifically, a measurable optical and gravimetric hydrogen response in alloys as low as 34% Pd is found, when previous works have suggested a disappearance of this response near 55% Pd. This result suggests that differences in film stress and microstructuring play a crucial role in the sorption behavior. We directly measure the thin film stress and morphology upon hydrogenation and show that the alloys have a substantially higher relative stress change than pure Pd, with the pure Pd data point falling 0.9 GPa below the expected trend line. Finally, we use the measured optical properties to illustrate the applicability of these alloys as grating structures and as a planar physical encryption scheme, where we show significant and variable changes in reflectivity upon hydrogenation. These results lay the foundation for the composition and design of next-generation hydrogen sensors and tunable photonic devices.

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Magnesium for Transient Photonics

Cited by 18 publications

References 46 publications

Nanophotonic Structural Colors

Nanophotonic Structural Colors

Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals

In Situ Optical and Stress Characterization of Alloyed Pd_xAu_1–xHydrides

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Magnesium for Transient Photonics

Cited by 18 publications

References 46 publications

Nanophotonic Structural Colors

Nanophotonic Structural Colors

Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals

In Situ Optical and Stress Characterization of Alloyed PdxAu1–xHydrides

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In Situ Optical and Stress Characterization of Alloyed Pd_xAu_1–xHydrides