Measuring Optical Properties of Advanced Nano/Micro-Periodic Structures Fabricated by Multi-Exposure Interference Lithography

2020 ◽  
Author(s):  
Shuzo Masui ◽  
Masaki Michihata ◽  
Kiyoshi Takamasu ◽  
Satoru Takahashi
Keyword(s):  
Periodic Structures ◽  
Low Cost ◽  
Industrial Applications ◽  
Interference Lithography ◽  
High Dispersion ◽  
Optical Elements ◽  
Precise Control ◽  
Periodic Grating ◽  
Interference Fringes ◽  
Multiple Interference

Abstract Functional optical elements based on nano/micro-periodic structures have attracted much attention. Since the fabrication of these dual-periodic structures requires precise control of periodicity, the semiconductor process such as an electron beam lithography has been mainly employed. However, these techniques have problems with expensive and low throughput for industrial applications. Therefore, there remains a need for low cost and high throughput fabrication methods of dual-periodic structures. Then we developed a multi-exposure interference lithography (MEIL) system using rotational Lloyd’s mirror interferometer to overcome these problems. The advantages of interference lithography are a large processing area and low cost. Our developed rotational Lloyd’s mirror setup enables us to a highly precise superposition of multiple interference fringes by multi-exposure. Furthermore, we developed a measurement setup for reflective diffractive elements using a two axial rotating stage and measured the diffraction properties of the fabricated dual-periodic diffraction gratings. In this paper, as a demonstration, we succeeded in the fabrication of high-dispersion diffraction grating with an enhanced diffraction efficiency of the −3rd order light. The fabricated shapes have a periodicity of 1997 nm and 665 nm. Furthermore, it was confirmed that the intensity of the −3rd order light was enhanced by about 10 times compared to the single periodic grating.

Coloration of Surfaces with Periodic Microstructures Replicated by Non-isothermal Precision Molding

2020 ◽  
Author(s):  
Yong Zhong ◽  
Ruxu Du ◽  
Lin Zhang ◽  
Allen Y. Yi
Keyword(s):  
Periodic Structures ◽  
Low Cost ◽  
Incident Light ◽  
Optical Diffraction ◽  
Molding Process ◽  
Structural Colors ◽  
Periodic Grating ◽  
Periodic Microstructures ◽  
Light Beams ◽  
Micro Structures

Abstract Micro/nano periodic structures are generally adopted in diffraction gratings. As an important optical component, the diffraction grating has the capability to split and diffract incident white light beams into iridescent beams dispersing to different directions. The appearance of coloration is a form of structural coloration by optical diffraction. In this paper, the non-isothermal precision molding is introduced for rapid & precise replication of periodic micro/nano grating structures, which are employed to render iridescent colors onto surfaces. Firstly, the effect of colorization and periodic grating profiles are theoretically analyzed. Secondly, different periodic micro gratings on silicon wafer, which are generally generated by photolithography, are employed in non-isothermal precision molding process as mold inserts. The molding result indicates that the periodic grating space and depth of grating structures can be precisely replicated from the mold inserts to polymer substrates. Subsequently, the split and iridescent color effects are demonstrated with monochromatic & white incident light beam and compared between samples with different periodic grating spaces. The optical effects of the replicated micro-structures confirm the feasibility of this method. The proposed non-isothermal precision molding process provides an alternative manufacturing option for realizing structural colors with large volume and low cost.

Fabrication of Nanostructured Hydrophobic Surfaces with Laser Interference Lithography

2013 ◽  
Vol 815 ◽  
pp. 457-464
Author(s):  
Hang Yu ◽  
Bing Rui Lu ◽  
Hui Li ◽  
Jian Ying Li ◽  
Ran Liu
Keyword(s):  
Periodic Structures ◽  
Low Cost ◽  
Substrate Surface ◽  
Interference Lithography ◽  
Laser Interference Lithography ◽  
Laser Interference ◽  
Large Area ◽  
Complex Processes ◽  
Submicron Scale ◽  
Potential Applications

The fabrication of large area nanoscale periodic structures on material surfaces for hydrophobicity engineering has been difficult due to the complex processes. Here we propose a two-step fabrication method for periodic nanostructures by combining laser interference lithography (LIL) and reactive ion etching (RIE). Sub-micron periodic nanotip patterns are fabricated in the photoresist by LIL, and then transferred into the silicon substrate using RIE. By measuring the contact angle (CA) of a water droplet on the substrate surface, the wettability of the surface with nanotip structures of various periods is studied. Our experiments show that the nanotip structures fabricated by the combined LIL and RIE process deliver satisfactory hydrophobic tendencies when the periods fall into the submicron scale. When the period of the structure is small enough, the hydrophilicity of the surface can be altered into hydrophobicity. The hydrophobicity achieved by this method is reusable and sustainable with low cost and no composition alteration comparing to chemical methods. The process developed in this work provides potential applications in biosensingand digital fluidics.

High quality diffractive optical elements (DOEs) using SMILE imprint technique

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Simon Drieschner ◽  
Fabian Kloiber ◽  
Marc Hennemeyer ◽  
Jan J. Klein ◽  
Manuel W. Thesen
Keyword(s):  
Soft Lithography ◽  
High Efficiency ◽  
Low Cost ◽  
Industrial Applications ◽  
Diffractive Optical Elements ◽  
Large Area ◽  
High Quality ◽  
Optical Elements ◽  
Uv Curable ◽  
Aspect Ratios

Abstract Augmented reality (AR) enhancing the existing natural environment by overlaying a virtual world is an emerging and growing market and attracts huge commercial interest into optical devices which can be implemented into head-mounted AR equipment. Diffractive optical elements (DOEs) are considered as the most promising candidate to meet the market’s requirements such as compactness, low-cost, and reliability. Hence, they allow building alternatives to large display headsets for virtual reality (VR) by lightweight glasses. Soft lithography replication offers a pathway to the fabrication of large area DOEs with high aspect ratios, multilevel features, and critical dimensions below the diffractive optical limit down to 50 nm also in the scope of mass manufacturing. In combination with tailored UV-curable photopolymers, the fabrication time can be drastically reduced making it very appealing to industrial applications. Here, we illustrate the key features of high efficiency DOEs and how the SMILE (SUSS MicroTec Imprint Lithography Equipment) technique can be used with advanced imprint photopolymers to obtain high quality binary DOEs meeting the market’s requirements providing a very versatile tool to imprint both nano- and microstructures.

Structrual Coloration of Surfaces With Microstructures Replicated by Non-Isothermal Precision Glass Molding

2020 ◽  
Author(s):  
Yong Zhong ◽  
Ruxu Du ◽  
Lin Zhang ◽  
Allen Y. Yi
Keyword(s):  
Periodic Structures ◽  
Low Cost ◽  
Incident Light ◽  
Molding Process ◽  
Glass Molding ◽  
Precision Glass Molding ◽  
Structural Colors ◽  
Periodic Grating ◽  
Light Beams ◽  
Micro Structures

Abstract Micro/nano periodic structures are generally adopted in diffraction gratings. As an important optical component, the diffraction grating has the capability to split and diffract incident white light beams into iridescent beams travelling in different directions. The emerging coloration is a form of structural coloration. In this paper, the non-isothermal precision glass molding is introduced for fast replication of periodic grating structures, which are employed to render iridescent colors on surfaces. Firstly, the effect of colorization and periodic grating profiles is theoretically analyzed. Secondly, different periodic micro gratings on silicon wafer, which are generally generated by photolithography, are employed in non-isothermal precision glass molding process as mold inserts. The molding result indicates that the periodic grating space and depth of grating structures can be precisely replicated from the mold inserts to polymer substrates. Subsequently, the split and iridescent color effects are demonstrated with monochromatic & white incident light beam and compared between samples with different periodic grating spaces. The optical effects of the replicated micro-structures confirm the feasibility of this method. The proposed non-isothermal precision glass molding process provides an alternative manufacturing option for realizing structural colors with large-volume and low-cost.

Real-Time Monitoring of Epitaxial Processes by Parallel-Polarized Reflectance Spectroscopy

MRS Bulletin ◽  
1995 ◽  
Vol 20 (5) ◽  
pp. 49-55 ◽  
Author(s):  
Nikolaus Dietz ◽  
Klaus J. Bachmann
Keyword(s):  
Real Time ◽  
Low Cost ◽  
Normal Incidence ◽  
Optical Probe ◽  
Reflectance Spectroscopy ◽  
Industrial Applications ◽  
Monitoring And Control ◽  
Real Time Monitoring ◽  
Spectral Ellipsometry ◽  
Precise Control

The engineering of advanced micro-electronic circuits, optoelectronic devices, and integrated optical circuits requires precise control of the lateral dimensions and thicknesses of device features and of the stoichiometry and doping of epitaxial semiconductor regions. This is preferably achieved by real-time monitoring and control of the individual deposition and etching processes that constitute the processing sequence. The use of optical probe techniques for the real-time monitoring of etching and/or growth processes is favored because of their nondestructive character and their potential use in real-time feedback control. Some of these methods are ideal in monitoring the overall growth process and/or substrate temperature in industrial applications, requiring low cost and maintenance. For example, in situ reflectance-spectroscopy methods, such as dynamic optical reflectivity (DOS), spectral-resolved normal incidence reflectance spectroscopy (MRS), or pyrometric interferometry (PI), are successfully applied to various deposition processes and provide information on both the growth rate and the composition of the deposits. However, small changes in the reflectance (because of chemical interactions at the surface of the films with the reactants supplied from the vapor phase) are of the order of 10−3 to 10−4 and are hardly observable with normal-incidence reflectance techniques because of the high reflectivity of substrate/film interface, which is typically of the order of 40%–60% for many semiconductors.In order to increase the sensitivity to surface- and interface-related growth properties, alternative optical-observation methods such as reflectance difference spectroscopy (RDS), surface photoabsorption (SPA), and spectral ellipsometry (SE) have been developed.

2D periodic structures patterned on 3D surfaces by interference lithography for SERS

2018 ◽  
Vol 461 ◽  
pp. 171-174 ◽  
Author(s):  
Ivana Lettrichova ◽  
Agata Laurencikova ◽  
Dusan Pudis ◽  
Jozef Novak ◽  
Matej Goraus ◽  
...  
Keyword(s):  
Periodic Structures ◽  
Interference Lithography ◽  
3D Surfaces

scholarly journals Remote Reflectivity Sensor for Industrial Applications

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1301
Author(s):  
Federico Cavedo ◽  
Parisa Esmaili ◽  
Michele Norgia
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Industrial Applications ◽  
Interference Immunity ◽  
Surface Reflection ◽  
Measurement Systems ◽  
Digital Detector ◽  
Reflected Light ◽  
Surface Optical ◽  
Diffused Light

A low-cost optical reflectivity sensor is proposed in this paper, able to detect the presence of objects or surface optical properties variations, at a distance of up to 20 m. A collimated laser beam is pulsed at 10 kHz, and a synchronous digital detector coherently measures the back-diffused light collected through a 1-inch biconvex lens. The sensor is a cost-effective solution for punctual measurement of the surface reflection at different distances. To enhance the interference immunity, an algorithm based on a double-side digital baseline restorer is proposed and implemented to accurately detect the amplitude of the reflected light. As results show, the sensor is robust against ambient light and shows a strong sensitivity on a wide reflection range. The capability of the proposed sensor was evaluated experimentally for object detection and recognition, in addition to dedicated measurement systems, like remote encoders or keyphasors, realized far from the object to be measured.

scholarly journals Deconstruction of Lignin: From Enzymes to Microorganisms

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2299
Author(s):  
Jéssica P. Silva ◽  
Alonso R. P. Ticona ◽  
Pedro R. V. Hamann ◽  
Betania F. Quirino ◽  
Eliane F. Noronha
Keyword(s):  
Microbial Communities ◽  
Metabolic Pathways ◽  
Low Cost ◽  
Direct Analysis ◽  
Industrial Applications ◽  
Natural Environments ◽  
Lignocellulosic Residues ◽  
Complementary Techniques ◽  
Plant Polymer ◽  
Powerful Strategy

Lignocellulosic residues are low-cost abundant feedstocks that can be used for industrial applications. However, their recalcitrance currently makes lignocellulose use limited. In natural environments, microbial communities can completely deconstruct lignocellulose by synergistic action of a set of enzymes and proteins. Microbial degradation of lignin by fungi, important lignin degraders in nature, has been intensively studied. More recently, bacteria have also been described as able to break down lignin, and to have a central role in recycling this plant polymer. Nevertheless, bacterial deconstruction of lignin has not been fully elucidated yet. Direct analysis of environmental samples using metagenomics, metatranscriptomics, and metaproteomics approaches is a powerful strategy to describe/discover enzymes, metabolic pathways, and microorganisms involved in lignin breakdown. Indeed, the use of these complementary techniques leads to a better understanding of the composition, function, and dynamics of microbial communities involved in lignin deconstruction. We focus on omics approaches and their contribution to the discovery of new enzymes and reactions that impact the development of lignin-based bioprocesses.

scholarly journals Enhanced catalytic ozonation of ibuprofen using a 3D structured catalyst with MnO2 nanosheets on carbon microfibers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guhankumar Ponnusamy ◽  
Hajar Farzaneh ◽  
Yongfeng Tong ◽  
Jenny Lawler ◽  
Zhaoyang Liu ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Active Sites ◽  
Low Cost ◽  
Three Dimensional ◽  
Industrial Applications ◽  
Catalytic Ozonation ◽  
Heterogeneous Catalytic ◽  
Structured Catalyst ◽  
Dimensional Network ◽  
Carbon Microfibers

AbstractHeterogeneous catalytic ozonation is an effective approach to degrade refractory organic pollutants in water. However, ozonation catalysts with combined merits of high activity, good reusability and low cost for practical industrial applications are still rare. This study aims to develop an efficient, stable and economic ozonation catalyst for the degradation of Ibuprofen, a pharmaceutical compound frequently detected as a refractory pollutant in treated wastewaters. The novel three-dimensional network-structured catalyst, comprising of δ-MnO2 nanosheets grown on woven carbon microfibers (MnO2 nanosheets/carbon microfiber), was synthesized via a facile hydrothermal approach. Catalytic ozonation performance of Ibuprofen removal in water using the new catalyst proves a significant enhancement, where Ibuprofen removal efficiency of close to 90% was achieved with a catalyst loading of 1% (w/v). In contrast, conventional ozonation was only able to achieve 65% removal efficiency under the same operating condition. The enhanced performance with the new catalyst could be attributed to its significantly increased available surface active sites and improved mass transfer of reaction media, as a result of the special surface and structure properties of this new three-dimensional network-structured catalyst. Moreover, the new catalyst displays excellent stability and reusability for ibuprofen degradation over successive reaction cycles. The facile synthesis method and low-cost materials render the new catalyst high potential for industrial scaling up. With the combined advantages of high efficiency, high stability, and low cost, this study sheds new light for industrial applications of ozonation catalysts.

scholarly journals Redox initiation in semicontinuous polymerization to search for specific mechanical properties of copolymers

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 613-623
Author(s):  
José Manuel Sandoval-Díaz ◽  
Francisco Javier Rivera-Gálvez ◽  
Marta Fernández-García ◽  
Carlos Federico Jasso-Gastinel
Keyword(s):  
Low Cost ◽  
Mechanical Analysis ◽  
Industrial Applications ◽  
Size Exclusion ◽  
Proton Nuclear Magnetic Resonance ◽  
Polymerization Reaction ◽  
Redox Initiation ◽  
Initiation System ◽  
Feeding Profile ◽  
Chain Composition

AbstractIn this work, for a semicontinuous emulsion polymerization reaction, it is shown that using a redox initiation system at 40°C, substantial modifications in copolymer chain composition with conversion can be easily obtained. To test controllable trajectories for comonomer feeding, linear and parabolic profiles were chosen to get different types of chain composition variations for the 50/50 w/w styrene/n-butyl acrylate system. For the “forced composition copolymers,” the molecular weight averages and distribution were obtained by size exclusion chromatography. The composition along conversion was followed by proton nuclear magnetic resonance to determine the weight composition distribution (WCD) of the copolymer chains. Mechanodynamic (dynamic-mechanical analysis), tensile, and hardness tests exhibited consistent results depending on the WCD that outcomes from the respective feeding profile. The results confirm that this methodology is of great potential for industrial applications when looking for synergy in copolymer properties, and low-cost processes.

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