Quasiperiodic air hole arrays for broadband and omnidirectional suppression of reflection

Patra, Anuradha; Ravishankar, Ajith P.; Nagarajan, Arvind; Maurya, Somendu; Achanta, Venu Gopal

doi:10.1063/1.4944438

Cited by 3 publications

(3 citation statements)

References 30 publications

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“…12,13 In addition to nanoporous AR coatings, there has been intense research in optical reflectionless potentials and reflection suppressing metamaterials in recent years. 14,15 The most common deposition methods for nanoporous AR coatings are spin-coating 3,9 and glancing angle deposition. [4][5][6]8,10,11 Neither of these techniques scales well to coating hundreds or thousands of components in parallel, nor do they permit coating all the surfaces of an object with a single run, though the obtained performances are excellent.…”

Section: Introductionmentioning

confidence: 99%

“…The increased porosity lowers the density, thus lowering the effective refractive index. Nanoporous materials have been studied vigorously as AR coatings for glass and other materials. − Often nanoporous AR coatings are manufactured with a gradient refractive index profile − due to the well-known broadband and omnidirectional AR properties a gradient-index layer provides. , In addition to nanoporous AR coatings, there has been intense research in optical reflectionless potentials and reflection suppressing metamaterials in recent years. , The most common deposition methods for nanoporous AR coatings are spin-coating , and glancing angle deposition. − ,,, Neither of these techniques scales well to coating hundreds or thousands of components in parallel, nor do they permit coating all the surfaces of an object with a single run, though the obtained performances are excellent.…”

Section: Introductionmentioning

confidence: 99%

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Grass-like Alumina with Low Refractive Index for Scalable, Broadband, Omnidirectional Antireflection Coatings on Glass Using Atomic Layer Deposition

Kauppinen

Isakov

Sopanen

2017

ACS Appl. Mater. Interfaces

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We present a new type of nanoporous antireflection (AR) coating based on grass-like alumina with a graded refractive index profile. The grass-like alumina AR coating is fabricated using atomic layer deposition (ALD) of alumina and immersion in heated deionized water. Optical transmittance of 99.5% at 500 nm was achieved with average transmittance of 99.0% in the range of 350-800 nm at normal incidence for double-sided coated glass. Angular spectral transmittance (0-80°) of the double-sided AR coated glass was also measured in the range of 350-800 nm and found to have mean spectral transmittance of 94.0% at 60°, 85.0% at 70°, and 53.1% at 80° angles of incidence, respectively. The grass-like alumina AR coating is suitable for mass production with the presented technique: even hundreds of optical components can be coated in parallel. Furthermore, as an ALD-based technique, the coating can be deposited conformally on surfaces with extreme topography, unlike many spin-coating, physical vapor deposition or glancing angle deposition-based coatings used today.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Grass-like Alumina with Low Refractive Index for Scalable, Broadband, Omnidirectional Antireflection Coatings on Glass Using Atomic Layer Deposition

Kauppinen

Isakov

Sopanen

2017

ACS Appl. Mater. Interfaces

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“…Superabsorbers can be classified into narrow-band absorbers [10] and broadband absorbers [11][12][13] depending on the absorption bandwidth. While narrow-band absorbers are generally used in sensing [14][15][16] and absorption filtering [17] , broadband absorbers find application in thermophotovoltaics [18,19] and anti-reflection surfaces [20][21][22][23] . Broadband absorption is realized by placing multiple resonators in a unit cell and have been demonstrated at various frequencies extending from optical to terahertz range [24][25][26][27][28][29][30][31][32][33] .…”

Section: Introductionmentioning

confidence: 99%

A Broadband Plasmonic Metasurface Superabsorber at Optical Frequencies: Analytical Design Framework and Demonstration

Nagarajan

Kumar

Shah

et al. 2018

Advanced Optical Materials

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Metasurface based superabsorbers exhibit near unity absorbance. While the absorption peak can be tuned by the geometry/size of the sub-wavelength resonator, broadband absorption can be obtained by placing multiple resonators of various size/shapes in a unit cell.Metal dispersion hinders high performance broadband absorption at optical frequencies and careful designing is essential to achieve good structures. We propose a novel analytical framework for designing a broadband superabsorber which is much faster than the time consuming full wave simulations that are employed so far. Analytical expressions are derived for the wavelength dependency of the design parameters, which are then used in the optimization of broadband absorption. Numerical simulations report an average polarizationindependent absorption of ~97% in the 450 -950 nm spectral region with a near unity absorption (99.36%) in the 500 -850 nm region. Experimentally, we demonstrate an average absorption over 98% in the 450-950 nm spectral region at 20° incident angle The designed superabsorber is polarization insensitive and has a weak launch angle dependency. The proposed framework simplifies the design process and provides a quicker optimal solution for high performance broadband superabsorbers

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Bioinspired Materials: From Distinct Dimensional Architecture to Thermal Regulation Properties

et al. 2022

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The structural evolutions of the organisms during the development of billions of years endow them with remarkable thermal-regulation properties, which have significance to their survival against the outer versatile environment. Inspired by the nature, there have been extensive researches to develop thermoregulating materials by mimicking and utilizing the advantages from the natural organisms. In this review, the latest advances in thermal regulation of bioinspired microstructures are summarized, classifying the researches from dimension. The representative materials are described with emphasis on the relationship between the structural features and the corresponding thermal-regulation functions. For one-dimensional materials, wild silkworm cocoon fibers have been involved, and the reasons for unique optical phenomena have been discussed. Pyramid cone structure, grating and multilayer film structure are chosen as typical examples of two-dimensional bionics. The excellent thermal performance of the three-dimensional network frame structures is the focus. Finally, a summary and outlook are given.

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Quasiperiodic air hole arrays for broadband and omnidirectional suppression of reflection

Cited by 3 publications

References 30 publications

Grass-like Alumina with Low Refractive Index for Scalable, Broadband, Omnidirectional Antireflection Coatings on Glass Using Atomic Layer Deposition

Grass-like Alumina with Low Refractive Index for Scalable, Broadband, Omnidirectional Antireflection Coatings on Glass Using Atomic Layer Deposition

A Broadband Plasmonic Metasurface Superabsorber at Optical Frequencies: Analytical Design Framework and Demonstration

Bioinspired Materials: From Distinct Dimensional Architecture to Thermal Regulation Properties

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