Antireflective glass nanoholes on optical lenses

Lee, Youngseop; Bae, Sunghan; Eom, Jaehyeon; Suh, Ho-Cheol; Jeong, Ki‐Hun

doi:10.1364/oe.26.014786

Cited by 25 publications

(24 citation statements)

References 32 publications

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“…The excess of the unreacted polymer is removed by immersing samples into pure toluene, left under a gentle stirring for 30 min, and finally dried under nitrogen flow. This process leaves a very thin film of ≈3–4 nm of grafted random copolymer . BCP solutions were thus deposited by 60 s spin coating on neutralized surfaces.…”

Section: Methodsmentioning

confidence: 99%

“…There is a plethora of techniques and processes used for the manufacture of nanostructures and, among the so called bottom‐up lithographic approaches, block copolymer (BCP) is one of the most promising and interesting ones . In previous years, this approach has demonstrated many applications in nanotechnology, such as the realization of antireflective optical lenses and structured photovoltaic with improved properties of harvesting and absorption . BCP is based on the self‐assembly (SA) of di‐ or tri‐block copolymers which generate a microphase separation toward well‐defined and self‐organized patterns.…”

Section: Introductionmentioning

confidence: 99%

“…The appealing of this method is due to the ability of overcoming the resolution limitations of the common lithographic techniques . The most used BCP‐SA exploits binary species, such as PS‐b‐PMMA . If they are subjected to a proper processing, as described below, they undergo to phase separation, with the appearance of circular nanocylinders of PMMA surrounded by a matrix of PS .…”

Section: Introductionmentioning

confidence: 99%

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Self‐Assembling of Block Copolymers with Alternative Solvents

Lombardo

D’Urso

Presti

et al. 2019

Macro Chemistry & Physics

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Block copolymer (BCP) lithography is one of the most technologically intriguing and scientifically interesting strategies for achieving nanometer‐sized features. This method usually exploits toluene as solvent for the deposition of BCPs in all the processing steps. However, this chemical has some technical disadvantages, such as high toxicity and hygroscopicity. The first aspect can limit its use on the industrial scale because of the protocols on the environmental and operator risks, while the second causes aging effects that can alter the results. In order to overcome these intrinsic limitations, a BCP self‐assembly (BCP‐SA) strategy is presented by using alternative deposition solvents in place of toluene. A preliminary study, based on the physical characteristics, such as volatility, polarity, and hygroscopicity, is carried out to explore two new alternative solvents, ethyl acetate and tetrahydrofuran. The effects on the BCP‐SA due to the new solvents are studied by SEM analysis supported by suitable software for the images elaboration. The results achieved show very promising outcomes for the polymer solutions obtained with ethyl acetate, in terms of uniformity of geometrical features, ordered areas extension, and homogeneity of the pattern obtained, making this chemical a good alternative to toluene.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Self‐Assembling of Block Copolymers with Alternative Solvents

Lombardo

D’Urso

Presti

et al. 2019

Macro Chemistry & Physics

View full text Add to dashboard Cite

show abstract

“…In particular, in multi-lens imaging system applications at broadband wavelengths (e.g., photo-thermal optical coherence tomography (OCT) and nonlinear optical (NLO) microscopy) [12][13][14], the optical losses of each single optical component are continuously accumulated, meaning that the performance of optical systems is significantly affected. Although research on nanostructures in relation to optical properties with curved surfaces, such as convex or concave optical lenses has been conducted, only a small body of results has been reported [15][16][17][18], and optical design with a theoretical background has not been sufficiently optimized for practical applications at a wide range of wavelengths. Among the results reported thus far, optical lenses using ARCs showed diffraction at a short wavelength of 300-400 nm, which resulted in a lower transmittance than conventional lenses at shorter wavelengths.…”

Section: Introductionmentioning

confidence: 99%

Double-Sided Anti-Reflection Nanostructures on Optical Convex Lenses for Imaging Applications

et al. 2019

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Anti-reflection coatings (ARCs) from the cornea nipple array of the moth-eye remarkably suppress the Fresnel reflection at the interface in broadband wavelength ranges. ARCs on flat glass have been studied to enhance the optical transmittance. However, little research on the implementation of ARCs on curved optical lenses, which are the core element in imaging devices, has been reported. Here, we report double-sided, bio-inspired ARCs on bi-convex lenses with high uniformity. We theoretically optimize the nanostructure geometry, such as the height, period, and morphology, since an anti-reflection property results from the gradually changed effective refractive index by the geometry of nanostructures. In an experiment, the transmittance of an ARCs lens increases up to 10% for a broadband spectrum without distortion in spot size and focal length. Moreover, we demonstrate ~30% improved transmittance of an imaging system composed of three bi-convex lenses, in series with double-sided ARCs (DARCs).

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“…A study explored a similar low-loss dielectric micro-lens with a nanopillar array with a variable diameter for infrared (IR) radiation on a silicon substrate [18]. Additionally, an antireflective optical lens with large-area glass nanohole arrays for optical imaging was reported [19,20]. However, most reports have not discussed the study of the focusing performance of micro-lens super-surface [21][22][23], which is extremely important to improve the energy utilization.…”

Section: Introductionmentioning

confidence: 99%

A Microlens Super-Surface Film with Regular Graded Circular Hole-Like Subwavelength Structures for Highly Focusing Strength

Zhang

et al. 2019

Coatings

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Using the fact that a sub-wavelength structure exhibits the same thermal expansion coefficient as a micro-lens array, we design a micro-lens super-surface film with regular circular hole-like subwavelength structures to realize the high performances of central highly focusing strength and short focal length. In addition, based on the Fresnel-Kirchhoff diffraction theory, the influences of subwavelength structural period and height on the focusing performance of a micro-lens are analyzed. Furthermore, the finite-difference time-domain method is utilized to optimize the structural parameters. Via direct laser writing and an inductively coupled plasma process, we fabricated a square micro-lens array consisting of a 1000 × 1000 micro-lens unit with a sub-wavelength structure, and the optical focusing performance was measured in the visible light band. Finally, the experimental results indicate that the focal length is decreased to 15 µm, the focal spot central energy is increased by 7.3%, and the light transmission, enhanced via inserting sub-wavelength structures, corresponds to 3%. This proves that the designed micro-lens array with a regular-graded circular hole-like subwavelength structure can achieve central high focusing and a short focal length. This has applications in several fields of wavefront detection and light field imaging systems.

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Antireflective glass nanoholes on optical lenses

Cited by 25 publications

References 32 publications

Self‐Assembling of Block Copolymers with Alternative Solvents

Self‐Assembling of Block Copolymers with Alternative Solvents

Double-Sided Anti-Reflection Nanostructures on Optical Convex Lenses for Imaging Applications

A Microlens Super-Surface Film with Regular Graded Circular Hole-Like Subwavelength Structures for Highly Focusing Strength

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