Control of spectral transmission enhancement properties of random anti-reflecting surface structures fabricated using gold masking

Peltier, Abigail H.; Sapkota, Gopal; Potter, Matthew G.; Busse, Lynda E.; Frantz, Jesse A.; Shaw, L. Brandon; Sanghera, Jasbinder S.; Aggarwal, Ishwar D.; Poutous, Menelaos K.

doi:10.1117/12.2252382

Cited by 12 publications

(6 citation statements)

References 6 publications

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“…The substrates are cleaned further, if needed, with an oxygen rich plasma. 37 When a single-sided rARSS FS substrate is compared to a plain bare FS window, its as-measured forward scattering distributions at 633 nm is negligible. Specifically, total integrated scatter of the rARSS surfaces is lower than eight-orders of magnitude in transmission with respect to the nominal transmission across the visible and NIR bands.…”

Section: Antireflective Treatment Of Air-glass Interfacesmentioning

confidence: 99%

Arrayed wide-field astronomical camera system for spectroscopic surveys on Extremely Large Telescopes: system architecture, proof-of-concept, and enabling technologies

Lee

Poutous

2021

J. Astron. Telesc. Instrum. Syst.

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The next generation Extremely Large Telescopes (ELTs) are promising a profound transformation of humanity's understanding of the universe by opening our eyes to a myriad of previously unseen astronomical objects across cosmic space time. Some of the key observational contributions to this transformation will, once again, be made through large-scale ultradeep spectroscopic surveys. Such surveys will call for a wide-field system to expand field of view and correct atmospheric dispersion beyond what an uncorrected ELT is canonically capable of. Although the traditional monolithic form of field correctors served our needs very well on 2-to 8-m class telescopes, we recognize challenges around scaling this traditional design to the ELT level, and hence, as detailed here, present a fundamentally different architecture, called the arrayed wide-field astronomical corrector system or AWACS, for the ELTs of two-mirror construction. The AWACS accomplishes field expansion via an array of small units populated over a telescope's focal surface, compensating for field aberrations and atmospheric dispersion locally but simultaneously. The AWACS units share one common electro-opto-mechanical design, permitting cost-effective high-volume part manufacturing. We detail the architectural features and proof-of-concept on-sky demonstration of the AWACS. In addition, we highlight our recent development results of randomly nano-textured antireflective (AR) surface structures in terms of an immediately viable, super-broadband, high-performance AR solution for not only the AWACS optics, but also broader ranges of electro-optical devices, particularly those subjected to harsh environments such as high-power laser, cryogenic, and space systems. With continuous advances in other relevant fields, the AWACS is uniquely positioned to enable, either by itself or by complementing traditional correctors, wide-field multi-object spectroscopic surveys in the ELT era and beyond. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Antireflective Treatment Of Air-glass Interfacesmentioning

confidence: 99%

Arrayed wide-field astronomical camera system for spectroscopic surveys on Extremely Large Telescopes: system architecture, proof-of-concept, and enabling technologies

Lee

Poutous

2021

J. Astron. Telesc. Instrum. Syst.

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“…A method to increase the size of rARSS to suit infrared optics involves a metal deposition and dewetting that generates quasi-periodic islands. This masking method has demonstrated the ability to tune the geometry, depth, and periodicity of the etch mask structures through variations in parameters such as deposition thickness and thermal annealing temperature [9,10]. These methods involved only one deposition and annealing step for etch mask formation.…”

Section: Arss Fabrication Methods (Periodic Vs Random)mentioning

confidence: 99%

Transmission enhancement via metasurfaces with tunable waveband performance by dewetting and seeded masking

Vaca,

Yoshino,

Benge

et al. 2024

Advanced Optics for Imaging Applications: UV Through LWIR IX

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This study demonstrates the fabrication of tunable masking layer consisting of gold islands on fused silica substrates. The goal is to produce anti-reflective structured surfaces (ARSS) that correlate to the repeatable and scalable masking step. The transmission enhancement waveband of fused silica is controlled by variations in gold masking islands created through repetitive dewetting process. Gold layer is formed by physical vapor deposition and thermal annealing. Varying deposition thickness and annealing temperature, size and periodicity of gold islands is controlled. With each iterative step of deposition and annealing, relative periodicity established by the initial island formation, or "seed", is maintained while increasing fill factor in subsequent iterations. Optical transmission spectra were analyzed of the masking layer and formation of metasurface by plasma etching. Results showed that larger deposition thicknesses required higher annealing temperatures to generate circular islands. The seed layer sets the mask periodicity, then the mask fill factor can be increased to allow for deeper etching of ARSS features, for broadband performance. For example, initial deposition thickness of 10 nm and repeated iterative steps of deposition and annealing, the fill factor increased (28%, 39%, 47%, 49%), while the island periodicity was maintained at average 91 ± 6 nm for all iterative steps. Etching these masked samples resulted in broadband transmission enhancement, over 94% of theoretical maximum. A comprehensive database of masking layer fabrication, resultant surface feature dimensions, and ARSS transmission enhancement capabilities was generated. This scalable masking approach can broaden high laser damage threshold applications utilizing tunable performance ARSS.

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“…The structured surfaces were fabricated using reactive ion etching (RIE) process under different processing conditions outlined in Table 1 and described elsewhere. 32 For baseline comparisons we included double-sided polished (WP) and single-sided polished (WR) silica substrates provided by the manufacturer. The sample A0 was fabricated with the same masking process as A1, W3 and W5, but it was not etched to completion.…”

Section: Conventional Surface Parametersmentioning

confidence: 99%

Organizational disorder of nanostructured antireflective surfaces

Srenevas,

Gonzalez,

Poutous

2024

Physics and Simulation of Optoelectronic Devices XXXII

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Surface nanostructure organizational entropy and spectral antireflective functionality relations have been recently suggested. They result from correlations between the onset of spectral transmission enhancement and surface grouped-feature separation collective disorder. Random antireflective surface structures (rARSS) enhance transmission by effectively reducing the electromagnetic impedance between optical indices across a boundary. Effective-medium approximation emulates the "random" structure surface layer with homogeneous films, failing to predict the critical wavelength above which the enhancement effect is observed. It is not clear as to what qualifies the "randomness" of rARSS, other than conventional profilometry measurements. We fabricated various rARSS silica surface modifications and quantified their randomness through Shannon's measure of nano-structural entropy. A surface organization state variable, granule population distributions, and spectral reflectivity suppression were related to disorder phase-transitions. Surface disorder parameter trends were compared to spectral measurements and simulations, to distinguish short-wavelength uncooperative nanostructure effects (bi-directional scatter) from cooperative effects (transmission enhancement.

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Control of spectral transmission enhancement properties of random anti-reflecting surface structures fabricated using gold masking

Cited by 12 publications

References 6 publications

Arrayed wide-field astronomical camera system for spectroscopic surveys on Extremely Large Telescopes: system architecture, proof-of-concept, and enabling technologies

Arrayed wide-field astronomical camera system for spectroscopic surveys on Extremely Large Telescopes: system architecture, proof-of-concept, and enabling technologies

Transmission enhancement via metasurfaces with tunable waveband performance by dewetting and seeded masking

Organizational disorder of nanostructured antireflective surfaces

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