Surface Relief Patterns Research Articles

Binary segmentation of relief patterns on point clouds

Analysis of 3D textures, also known as relief patterns is a challenging task that requires separating repetitive surface patterns from the underlying global geometry. Existing works classify entire surfaces based on one or a few patterns by extracting ad-hoc statistical properties. Unfortunately, these methods are not suitable for objects with multiple geometric textures and perform poorly on more complex shapes. In this paper, we propose a neural network for binary segmentation to infer per-point labels based on the presence of surface relief patterns. We evaluated the proposed architecture on a high resolution point cloud dataset, surpassing the state-of-the-art, while maintaining memory and computation efficiency.

ТЕХНОЛОГІЇ СТВОРЕННЯ ПОВЕРХНЕВИХ РЕЛЬЄФІВ НА ПЛІВКАХ ХАЛЬКОГЕНІДНИХ НАПІВПРОВІДНИКІВ

A review of recent progress in optical recording of surface relief structures in the films of amorphous chalcogenides is presented. Various aspects related to light-driven macroscopic effects for these materials (changes in solubility, local evaporation, volume changes, mass-transport and so on) where stimulated surface patterning takes place due to the interaction of matter with light are discussed. Experimental data describing different aspects of surface relief patterning using direct recording by tigtly focused single or structured light beams are summarized.

Influence of heating temperature on the optical response properties and surface relief patterns of TiO2/GeO2/ormosils composite films containing azobenzene

With the progress of modern integrated optical technology, organic-inorganic composite materials have been widely used in integrated optoelectronic devices. Because of satisfying optical response properties among azobenzene, it will be an ideal choice to introduce the material into organic-inorganic composite materials. TiO2/GeO2/ormosils composite films containing azobenzene were prepared by combining the solgel technique with the spin-coating process. The optical transmission modes and loss of as-prepared samples at different transmission wavelengths were researched by a prism coupler. The result shows that the composite film is multi-mode transmission at the transmission wavelength of 633 nm and single-mode transmission at 1538 nm. The transmission loss is sufficient for applications in optical elements. The response properties and Fourier transform infrared spectroscopy of as-prepared samples at different heating temperatures were also studied. The composite films obtained at 50°C have the best optical response properties. Furthermore, the banding energy and chemical composition among the films were measured through x-ray photoelectron spectroscopy. Finally, the surface topography of as-prepared samples was observed by atomic force microscopy. The surface of the composite film appears with patterns of relief under the appropriate temperature. The above results show that the as-prepared TiO2/GeO2/ormosils composite films containing azobenzene will be a kind of ideal material in the field of integrated optics applications.

Insight and Recent Advances into the Role of Topography on the Cell Differentiation and Proliferation on Biopolymeric Surfaces.

It is well known that surface topography plays an important role in cell behavior, including adhesion, migration, orientation, elongation, proliferation and differentiation. Studying these cell functions is essential in order to better understand and control specific characteristics of the cells and thus to enhance their potential in various biomedical applications. This review proposes to investigate the extent to which various surface relief patterns, imprinted in biopolymer films or in polymeric films coated with biopolymers, by utilizing specific lithographic techniques, influence cell behavior and development. We aim to understand how characteristics such as shape, dimension or chemical functionality of surface relief patterns alter the orientation and elongation of cells, and thus, finally make their mark on the cell proliferation and differentiation. We infer that such an insight is a prerequisite for pushing forward the comprehension of the methodologies and technologies used in tissue engineering applications and products, including skin or bone implants and wound or fracture healing.

Photopatterning via photofluidization of azobenzene polymers

In current photo-based patterning techniques, an image is projected onto a photosensitive material to generate a pattern in the area where the light is focused. Thus, the size, shape, and periodicity of the pattern are determined by the features on the photomask or projected images, and the materials themselves generally do not play an active role in changing the features. In contrast, azobenzene polymers offer a unique type of photopatterning platform, where photoisomerization of the azobenzene groups can induce substantial material movements at the molecular, micro-, and macroscales. Stable surface relief patterns can be generated by exposure to interference light beams. Thus, periodic nano- and microstructures can be fabricated with both two- and three-dimensional spatial control over a large area in a remarkably simple way. Polarized light can be used to guide the flow of solid azobenzene polymers along the direction of light polarization via an unusual solid-to-liquid transition, allowing for the fabrication of complex structures using light. This review summarizes the recent progress in advanced manufacturing using azobenzene polymers. This includes a brief introduction of the intriguing optical behaviors of azobenzene polymers, followed by discussions of the recent developments and successful applications of azobenzene polymers, especially in micro- and nanofabrication.

Precise Thermoplastic Processing of Graphene Oxide Layered Solid by Polymer Intercalation

HighlightsA solvent-free thermoplastic forming processing of graphene materials is invented by polymer intercalation from graphene oxide precursor.The correlation between interlayer spacing and thermoplastic forming capability of polymer-intercalated graphene oxide solid is uncovered.The multi-scale forming of graphene materials from Gaussian curved shapes to surface relief patterns with size precision down to 360 nm is realized.

Accelerated method for the alclad alloy fatigue curve construction by the surface relief pattern

Highlights Action of fluctuating loads leads to the formation of the surface deformation relief. The intensity of the surface deformation relief indicates accumulated fatigue damage. The surface relief at the initial stage of the metal fatigue is extremely informative. The initial rate of the damage provides the possibility to construct a fatigue curve.

Angle‐Insensitive Fabry–Perot Mechanochromic Sensor for Real‐Time Structural Health Monitoring

AbstractColorimetric sensors that respond to mechanical stimuli have garnered increased attention for various applications such as healthcare, display, electronic skin, and camouflage. To date, these mechanochromic sensors have been largely fabricated and studied with periodic structures such as surface relief patterns and photonic crystals. Although periodic structures can provide high wavelength selectivity, the strong viewing‐angle‐dependence of the color hinders their practical application in indoor and outdoor environments. Herein, a Fabry–Perot (F–P) interferometer composed of an elastomeric triblock copolymer as a dielectric spacer sandwiched between two metal layers is presented as an angle‐insensitive mechanochromic sensor. The planar structure of this device, formed on a flexible substrate, can be stretched to strains greater than 100%, and it reveals diverse colors according to the applied strain. The revealed colors are highly independent of the viewing angle, as confirmed both experimentally and theoretically. The developed sensor can be attached to any material including metals to visually detect mechanical failures (cracking, cleavage, and deformation) of the material. Therefore, this F–P mechanochromic sensor shows significant potential for real‐time structural health monitoring.

Multifunctional Structured Platforms: From Patterning of Polymer-Based Films to Their Subsequent Filling with Various Nanomaterials.

There is an astonishing number of optoelectronic, photonic, biological, sensing, or storage media devices, just to name a few, that rely on a variety of extraordinary periodic surface relief miniaturized patterns fabricated on polymer-covered rigid or flexible substrates. Even more extraordinary is that these surface relief patterns can be further filled, in a more or less ordered fashion, with various functional nanomaterials and thus can lead to the realization of more complex structured architectures. These architectures can serve as multifunctional platforms for the design and the development of a multitude of novel, better performing nanotechnological applications. In this work, we aim to provide an extensive overview on how multifunctional structured platforms can be fabricated by outlining not only the main polymer patterning methodologies but also by emphasizing various deposition methods that can guide different structures of functional nanomaterials into periodic surface relief patterns. Our aim is to provide the readers with a toolbox of the most suitable patterning and deposition methodologies that could be easily identified and further combined when the fabrication of novel structured platforms exhibiting interesting properties is targeted.

Digital holographic microscopy for real-time observation of surface-relief grating formation on azobenzene-containing films

Light-induced surface structuring of azobenzene-containing films allows for creation of complex surface relief patterns with varying heights, patterns which would be difficult to create using conventional lithography tools. In order to realize the full potential of these patternable surfaces, understanding their formation dynamics and response to different types of light fields is crucial. In the present work we introduce digital holographic microscopy (DHM) for real time, in-situ observation of surface-relief grating (SRG) formation on azobenzene-containing films. This instrument allows us to measure the surface topography of films while illuminating them with two individually controlled laser beams for creating periodically varying patterns. By utilizing the information of the grating formation dynamics, we combine multiple grating patterns to create pixels with wide gamut structural colors as well as blazed grating structures on the film surface. As long as the material behaviour is linear, any Fourier optical surface can be created utilizing this multiple patterning approach. The DHM instrument presented here has the potential for creating complex 3D surface reliefs with nanometric precision.

THE FORMATION OF SURFACE NANOSTRUCTURES ON As-S-Ge CHALCOGENIDE FILM AFTER E-BEAM EXPOSURE

Проблематика. Халькогенідні стекла формують унікальний клас матеріалів та є привабливими з точки зору їх різноманітних застосувань, що обумовлені їхніми непересічними властивостями та можливістю утворювати поверхневий рельєф. Взаємодія цих матеріалів з електронним променем становить інтерес через різноманітність фізичних явищ, спричинених у халькогенідних плівках лазерним опроміненням. Мета дослідження. Дослідження прямого (без селективного травлення) формування поверхневого рельєфу періодичних наноструктур на плівці As 3 S 77 Ge 20 товщиною ~8,3 мкм, виготовленій вакуумним термічним випаровуванням, із використанням електронно-променевої літографії. Вивчення зміни висоти і форми поверхневих наноструктур залежно від дози опромінення. Методика реалізації. Хімічний склад плівки визначали за допомогою енергетично-дисперсійного аналізу рентгенівських променів. Плівку опромінювали електронним променем за допомогою скануючого електронного мікроскопа. Було досліджено вплив опромінення електронним пучком на аморфну халькогенідну тонку плівку As 3 S 77 Ge 20 . Поверхневий рельєф плівки сканували атомно-силовим мікроскопом. Результати дослідження. Доза експозиції G варіювалась від 12 мКл·см - 2 до 12 Кл·см - 2 . Було виявлено формування конусів із гаусовим профілем на поверхнях плівок після локального опромінення електронами. Встановлено залежність висоти одержаних поверхневих наноструктур від дози експозиції. Видно, що для G 2400 мКл·см - 2 вона зменшується. Було знайдено початкову та інверсійну дози формування поверхневого рельєфу. Для матриць із відстанню між точками опромінення d = 6,6 мкм початкова доза становила G 0 = 9,60 мКл·см - 2 , а інверсійна – G i = 31,18 Кл·см - 2 . Для d = 10 мкм ці параметри дорівнювали G 0 = 6,98 мКл·см - 2 і G i = 36,19 Кл·см - 2 . Залежності у зростаючому інтервалі дози (від 16 до 1200 мКл·см - 2 ) для d = 6,6 мкм і d = 10 мкм було апроксимовано експоненційними функціями. Висновки. Зміну форми та параметрів отриманого рельєфу поверхні на плівці As 3 S 77 Ge 20 можна пояснити моделлю акумулювання заряду. Наші дослідження показали, що вивчена композиція As 3 S 77 Ge 20 придатна для запису електронним променем та може бути використана для виготовлення оптичних елементів.

The surface relief pattern influence on the strain-stress state of the Si3N4-ceramics' basic structure elements under the steady-state heat transfer

The regularities of the relief pattern and thermal load influence on the temperature and stress intensity was determined for the nitride ceramics basic structural components located in its surface layer. It was proposed to use these regularities to the design-technology data basis development for the engineering and manufacturing of the ceramic hardware and tools.

Optimizing Micromixer Surfaces To Deter Biofouling.

Using computational modeling, we show that the dynamic interplay between a flowing fluid and the appropriately designed surface relief pattern can inhibit the fouling of the substrate. We specifically focus on surfaces that are decorated with three-dimensional (3D) chevron or sawtooth "micromixer" patterns and model the fouling agents (e.g., cells) as spherical microcapsules. The interaction between the imposed shear flow and the chevrons on the surface generates 3D vortices in the system. We pinpoint a range of shear rates where the forces from these vortices can rupture the bonds between the two mobile microcapsules near the surface. Notably, the patterned surface offers fewer points of attachment than a flat substrate, and the shear flows readily transport the separated capsules away from the layer. We contrast the performance of surfaces that encompass rectangular posts, chevrons, and asymmetric sawtooth patterns and thereby identify the geometric factors that cause the sawtooth structure to be most effective at disrupting the bonding between the capsules. By breaking up nascent clusters of contaminant cells, these 3D relief patterns can play a vital role in disrupting the biofouling of surfaces immersed in flowing fluids.

High-performance light diffuser films by hierarchical buckling-based surface texturing combined with internal pores generated from physical gelation induced phase separation of binary polymer solution

Abstract A simple and low-cost process has been demonstrated for the fabrication of high-performance light diffuser films. Instead of polymer composites with light diffusing micro/nanoparticles as in typical approaches, low refractive-index (RI) air pockets or pores have been included inside the diffuser film, which has large RI contrast to host polymer matrix. The generation of such pores has been enabled by elastomeric polydimethylsiloxane (PDMS) assisted fast drying of binary polymer solution, where physical gelation induced phase separation generates pores inside the dried film. To further increase the light scattering and thus the optical haze of such diffuser films, hierarchical buckling of PDMS surface by oxygen plasma treatment has been applied. The buckled PDMS could be directly integrated into the PDMS-assisted drying process, thereby enables one to fabricate high-performance diffuser films having both surface-relief patterns and internal pores at the same time. This unique combination of surface and volume scatterings has yielded high-performance light diffusing films with high transmittance and haze simultaneously.

Synthesis and Characterization of Photoprocessable Lignin-Based Azo Polymer

Lignin-based azo polymer-bearing pseudo-stilbene-type azo chromophores have been synthesized by a post-azo coupling reaction between the modified alkali lignin and diazonium salts of 4-aminobenzoic acid in DMF with high yield. The polymer synthesized was characterized by using spectroscopic methods. Significant dichroism and surface relief patterns could be photoinscribed on the prepared azo polymer films by using appropriate laser beams. Self-assembly of the lignin-based polymer in selective solvents (THF/H2O) can give uniform colloidal spheres, which can be elongated along the polarization direction of the irradiation light. This novel synthesized lignin-based azo polymer could potentially be used for applications such as reversible optical data storage, photoswitching, sensors, and other photo-driven devices, which provide a simple strategy for value-added utilization of lignin biomass resources.

Fabrication of fluorescent surface relief patterns using AIE polymer through a soft lithographic approach

A new aggregation-induced emission (AIE) active polymer (PS-TPE) with high tetraphenylethene (TPE) loading density was synthesized. The synthesized polymer showed significant AIE properties, good solubility and high thermal stability. Soft-lithographic contact printing process by using photoinduced surface relief structures on azo polymer film as masters and duplicated PDMS elastomer as stamps was used to fabricate fluorescent PS-TPE patterns. Various fluorescent structures with high contrast including surface relief gratings, periodically dotted patterns, and quasi-crystal structures can be easily fabricated through this approach. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1838–1845

Continuous distributed phase-plate advances for high-energy laser systems

The distributed phase plate (DPP) design code Zhizhoo’ has been used to design full- aperture, continuous near-field transmission optics for a wide variety of high-fidelity focal-spot shapes for high-energy laser systems: OMEGA EP, Dynamic Compression Sector (DCS), and the National Ignition Facility (NIF). The envelope shape, or profile, of the focal spot affects the hydrodynamics of directly driven targets in these laser systems. Controlling the envelope shape to a high degree of fidelity impacts the quality of the ablatively driven implosions. The code Zhizhoo’ not only produces DPP's with great control of the envelope shape, but also spectral and gradient control as well as robustness from near-field phase aberrations. The focal-spot shapes can take on almost any profile from symmetric to irregular patterns and with high fidelity relative to the objective function over many decades of intensity. The control over the near-field phase spectrum and phase gradients offer greater manufacturability of the full- aperture continuous surface-relief pattern. The flexibility and speed of the DPP design code Zhizhoo’ will be demonstrated by showing the wide variety of successful designs that have been made and those that are in progress.

Silicon-based nanostructures formed by plasma etching through a mask formed by a focused beam of Ga+ ions

A method of formation of three-dimensional silicon-based nanostructures by a mask formation with the use of focused ion beam, for following plasma etching, is presented. A surface relief pattern, with depths of less than 80 nm, dependent on a dose of interstitial ions, was formed by plasma etching of an undoped area. A range of values of a dose of Ga+ ion beam for silicon doping was determined. Three-dimensional silicon-based structures with linear dimensions of about 100 nanometers were obtained.

Fabrication of Periodically Poled Lithium Niobate by Direct Laser-Writing and Its Poling Quality Evaluation

We fabricated a periodically poled lithium niobate (PPLN) by direct laser-writing of a quasi-phase-matching (QPM) structure in photolithographic process. Because we do not need to prepare a photomask by electron-beam writing, the "maskless" process shortens the fabrication time and significantly reduces the cost. We evaluated the poling quality of the direct laser-written PPLN by measuring the diffraction noise from the surface relief pattern of the fabricated QPM grating and comparing the results to those from a conventional PPLN made with a photomask. The quality of the PPLN fabricated by direct laser-writing was shown to be equivalent to that fabricated by the conventional method.

Multidirectional Light‐Harvesting Enhancement in Dye Solar Cells by Surface Patterning

One dimensional gratings patterned on the surface of nanocrystalline titania electrodes are used as a light harvesting strategy to improve the overall performance of dye solar cells under both frontal and rear illumination conditions. A soft‐lithography‐based micromoulding approach is employed to replicate a periodic surface relief pattern onto the surface of the electrode, which is later sensitized with a dye. As the patterned surface acts as an optical grating both in reflection and transmission modes, its effect is to increase the light path of diffracted beams within the absorbing layer when it is irradiated either from the electrode or the counter electrode for a broad range of angles of incidence on each surface. Full optical and photovoltaic characterization demonstrates not only the optical quality of the patterned surfaces but also the multidirectional character of the enhancement of light harvesting and conversion efficiency. The approach herein presented thus permits to preserve the operation of the cell when irradiated from its two faces while increasing its overall power conversion efficiency. This feature is a key advantage over other light harvesting efficiency enhancing methods, such as the deposition of a back diffuse scattering layer, in which the performance of the cell under illumination from one of its sides is enlarged at the expense of reducing the output under reverse irradiation conditions.