Holographic laser processing for three-dimensional photonic lattices

2017 ◽  
Author(s):  
Satoru Shoji ◽  
Remo Proietti Zaccaria ◽  
Satoshi Kawata
Keyword(s):  
Lattice Constant ◽  
Laser Processing ◽  
Periodic Structures ◽  
Three Dimensional ◽  
Processing Method ◽  
Direct Writing ◽  
Photosensitive Polymers ◽  
Photonic Lattices ◽  
Lattice Symmetry ◽  
Beam Technique

This article describes a holographic laser-processing method for independently controlling the lattice symmetry and lattice constant in three-dimensional photonic lattices. With this approach, optical periodicity is created in lower dimensions and three-dimensional periodicity is obtained by a combination of several lower-dimensional periodic structures. The proposed holographic laser-processing method is compared with the standard four-beam technique. Examples of experimental demonstration achieved in photosensitive polymers are given. The article also introduces a multiphoton direct-writing technique for creating defect structures in lattices towards production of defect cavity-functionalized photonic crystal devices. It shows that all Bravais lattices can be produced by choosing proper incident vectors of laser beams. The lattice constant of the structure can be changed without distorting its lattice symmetry and lattice elements.

scholarly journals Direct Laser Processing of Two-Scale Periodic Structures for Superhydrophobic Surfaces Using a Nanosecond Pulsed Laser

2020 ◽  
Vol 7 (4) ◽  
pp. 496-512 ◽  
Author(s):  
Hidenori Shimada ◽  
Shunichi Kato ◽  
Takumi Watanabe ◽  
Masaki Yamaguchi
Keyword(s):  
Contact Angle ◽  
Laser Processing ◽  
Periodic Structures ◽  
Pulsed Laser ◽  
Processing Method ◽  
Superhydrophobic Surfaces ◽  
Processing Rate ◽  
Nanosecond Pulsed Laser ◽  
Direct Laser ◽  
Micro Holes

AbstractHierarchical structures are promising geometries for superhydrophobic surfaces, however a processing method with a single laser light source that is capable of both one-pass and rapid processing has not been established. The purpose of this study was to propose a concept of direct laser processing of two-scale periodic structures exhibiting superhydrophobicity. We hypothesized that the molten material that occurs due to the expanding plasma and that is squeezed around the micro-holes could play an active role in the processing of two-scale periodic structures. Percussion drilling using a nanosecond pulsed laser (532 nm wavelength) was performed on a steel surface. Twenty four different test-pieces were prepared using pitch (16–120 μm), number of repetition shots (1–120), and fluence (2.49–20 J/cm2), as the parameters. As the results, micro-holes with bank-shaped outer rims were formed. The maximum apparent contact angle was 161.4° and the contact angle hysteresis was 4.2° for a pitch of 80 μm and 20 repetition shots. The calculated results for the apparent contact angles were consistent with the measured results. Finally, an equation for estimating the processing rate was proposed. We demonstrated that this direct processing method can achieve a maximum processing rate of 823 mm2/min.

A Prediction Model for Ablation Fluence Threshold in Femtosecond Laser Processing of Fused Silica

2017 ◽  
Vol 5 (3) ◽  
Author(s):  
Han Wang ◽  
Hong Shen
Keyword(s):  
Femtosecond Laser ◽  
Laser Processing ◽  
Three Dimensional ◽  
Ionization Rate ◽  
Fused Silica ◽  
Published Data ◽  
Direct Writing ◽  
Femtosecond Laser Processing ◽  
Ideal Tool ◽  
Improved Model

The manufacture of micro–nano structures in transparent dielectrics is becoming increasingly important due to the applications in medical and biological sciences. The femtosecond pulsed laser, with its selectivity, high precision, and three-dimensional direct writing nature, is an ideal tool for this processing technology. In this paper, an improved model for the prediction of ablation crater shape and fluence threshold in femtosecond laser processing of fused silica is presented, in which self-trapping excitons and electrons' relaxation are involved to depict ionization process, Thornber's and Keldysh's models are employed to estimate ionization rate precisely, and a novel ablation criterion is proposed to judge ablation. Moreover, the relationship between the ablation fluence threshold and laser pulse duration is investigated with three different extrapolation methods. The results indicate that no matter which extrapolation method is employed, the ablation fluence thresholds predicted by the presented model agree with the published data.

Crosstalk Minimization Method for Eye-tracking-based 3D Display

2020 ◽  
Author(s):  
Seok Lee ◽  
Juyong Park ◽  
Dongkyung Nam
Keyword(s):  
Image Processing ◽  
Eye Tracking ◽  
Three Dimensional ◽  
Processing Method ◽  
Eye Position ◽  
Relative Location ◽  
3D Display ◽  
Minimization Method ◽  
3D Crosstalk ◽  
Pixel Value

In this article, the authors present an image processing method to reduce three-dimensional (3D) crosstalk for eye-tracking-based 3D display. Specifically, they considered 3D pixel crosstalk and offset crosstalk and applied different approaches based on its characteristics. For 3D pixel crosstalk which depends on the viewer’s relative location, they proposed output pixel value weighting scheme based on viewer’s eye position, and for offset crosstalk they subtracted luminance of crosstalk components according to the measured display crosstalk level in advance. By simulations and experiments using the 3D display prototypes, the authors evaluated the effectiveness of proposed method.

Recent Patents on Micro-EDM Milling

2020 ◽  
Vol 13 (3) ◽  
pp. 219-229
Author(s):  
Baocheng Xie ◽  
Jianguo Liu ◽  
Yongqiu Chen
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Three Dimensional ◽  
Processing Method ◽  
Electrode Wear ◽  
Micro Edm ◽  
Processing Efficiency ◽  
Processing Methods ◽  
Machining Quality ◽  
Micro Electrical Discharge Machining

Background: Micro-Electrical Discharge Machining (EDM) milling is widely used in the processing of complex cavities and micro-three-dimensional structures, which is a more effective processing method for micro-precision parts. Thus, more attention has been paid on the micro-EDM milling. Objective : To meet the increasing requirement of machining quality and machining efficiency of micro- EDM milling, the processing devices and processing methods of micro-EDM milling are being improved continuously. Methods: This paper reviews various current representative patents related to the processing devices and processing methods of micro-EDM milling. Results: Through summarizing a large number of patents about processing devices and processing methods of micro-EDM milling, the main problems of current development, such as the strategy of electrode wear compensation and the development trends of processing devices and processing methods of micro-EDM milling are discussed. Conclusion: The optimization of processing devices and processing methods of micro-EDM milling are conducive to solving the problems of processing efficiency and quality. More relevant patents will be invented in the future.

scholarly journals Imaging of bi-anisotropic periodic structures from electromagnetic near-field data

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Dinh-Liem Nguyen ◽  
Trung Truong
Keyword(s):  
Inverse Scattering ◽  
Maxwell Equations ◽  
Field Data ◽  
Periodic Structures ◽  
Near Field ◽  
Scattering Problem ◽  
Three Dimensional ◽  
Inverse Scattering Problem ◽  
Factorization Method ◽  
Unique Determination

AbstractThis paper is concerned with the inverse scattering problem for the three-dimensional Maxwell equations in bi-anisotropic periodic structures. The inverse scattering problem aims to determine the shape of bi-anisotropic periodic scatterers from electromagnetic near-field data at a fixed frequency. The factorization method is studied as an analytical and numerical tool for solving the inverse problem. We provide a rigorous justification of the factorization method which results in the unique determination and a fast imaging algorithm for the periodic scatterer. Numerical examples for imaging three-dimensional periodic structures are presented to examine the efficiency of the method.

Image Processing Based on Three-Dimensional Stereo Vision

2014 ◽  
Vol 556-562 ◽  
pp. 5017-5020
Author(s):  
Ting Ting Wang
Keyword(s):  
Image Processing ◽  
Binocular Vision ◽  
Stereo Vision ◽  
Error Rate ◽  
Three Dimensional ◽  
Processing Method ◽  
Stereoscopic Vision ◽  
Average Error ◽  
Traditional Model ◽  
Average Error Rate

Three-dimensional stereo vision technology has the capability of overcoming drawbacks influencing by light, posture and occluder. A novel image processing method is proposed based on three-dimensional stereoscopic vision, which optimizes model on the basis of camera binocular vision and in improvement of adding constraints to traditional model, moreover ensures accuracy of later location and recognition. To verify validity of the proposed method, firstly marking experiments are conducted to achieve fruit location, with the result of average error rate of 0.65%; and then centroid feature experiments are achieved with error from 5.77mm to 68.15mm and reference error rate from 1.44% to 5.68%, average error rate of 3.76% while the distance changes from 300mm to 1200mm. All these data of experiments demonstrate that proposed method meets the requirements of three-dimensional imageprocessing.

scholarly journals Advanced Micro-Actuator/Robot Fabrication Using Ultrafast Laser Direct Writing and Its Remote Control

2020 ◽  
Vol 10 (23) ◽  
pp. 8563
Author(s):  
Sangmo Koo
Keyword(s):  
Three Dimensional ◽  
Processing Technique ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Precise Control ◽  
Two Photon ◽  
Non Invasive ◽  
Acoustic Control ◽  
Fs Laser ◽  
Invasive Control

Two-photon polymerization (TPP) based on the femtosecond laser (fs laser) direct writing technique in the realization of high-resolution three-dimensional (3D) shapes is spotlighted as a unique and promising processing technique. It is also interesting that TPP can be applied to various applications in not only optics, chemistry, physics, biomedical engineering, and microfluidics but also micro-robotics systems. Effort has been made to design innovative microscale actuators, and research on how to remotely manipulate actuators is also constantly being conducted. Various manipulation methods have been devised including the magnetic, optical, and acoustic control of microscale actuators, demonstrating the great potential for non-contact and non-invasive control. However, research related to the precise control of microscale actuators is still in the early stages, and in-depth research is needed for the efficient control and diversification of a range of applications. In the future, the combination of the fs laser-based fabrication technique for the precise fabrication of microscale actuators/robots and their manipulation can be established as a next-generation processing method by presenting the possibility of applications to various areas.

Optical tuning of three-dimensional photonic crystals fabricated by femtosecond direct writing

2005 ◽  
Vol 87 (9) ◽  
pp. 091117 ◽  
Author(s):  
Dennis McPhail ◽  
Martin Straub ◽  
Min Gu
Keyword(s):  
Photonic Crystals ◽  
Three Dimensional ◽  
Direct Writing

Groove Shape Optimization of Thrust Air Bearing for Small Size Spindle Considering the Processing Errors

2018 ◽  
Author(s):  
Masayuki Ochiai ◽  
Naoya Kato ◽  
Hiromu Hashimoto
Keyword(s):  
Probability Distribution ◽  
Laser Processing ◽  
Thrust Bearing ◽  
Groove Depth ◽  
Spindle Motor ◽  
Processing Method ◽  
Optimum Shape ◽  
Air Bearing ◽  
Machining Error ◽  
Processing Errors

In this research, we aim to examine the usefulness of the newly developed spindle motor proposed by Ochiai. Since machining error due to tool wear etc. used for microfabrication can be ignored, laser processing was used as a processing method. Thrust bearing grooves were generated by laser processing, and variation in groove depth was observed. Finally, the optimum shape of the thrust bearing groove was obtained by robust optimization using the probability distribution that can be approximated from the obtained machining error.

scholarly journals Rapid Fabrication of Continuous Surface Fresnel Microlens Array by Femtosecond Laser Focal Field Engineering

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 112 ◽  
Author(s):  
Linyu Yan ◽  
Dong Yang ◽  
Qihuang Gong ◽  
Yan Li
Keyword(s):  
Femtosecond Laser ◽  
Three Dimensional ◽  
Fresnel Lens ◽  
Two Dimensional ◽  
Direct Writing ◽  
Lens Array ◽  
Two Photon ◽  
Rapid Fabrication ◽  
Continuous Surface ◽  
Two Photon Polymerization

Femtosecond laser direct writing through two-photon polymerization has been widely used in precision fabrication of three-dimensional microstructures but is usually time consuming. In this article, we report the rapid fabrication of continuous surface Fresnel lens array through femtosecond laser three-dimensional focal field engineering. Each Fresnel lens is formed by continuous two-photon polymerization of the two-dimensional slices of the whole structure with one-dimensional scan of the corresponding two-dimensional engineered intensity distribution. Moreover, we anneal the lens array to improve its focusing and imaging performance.

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