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Iberoamerican Meeting of Optics and the Latin American Meeting of Optics, Lasers and Their Applications最新文献

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New developments on the design and modeling of fiber optical tweezers 光纤镊子设计与建模的新进展
R. S. Rodrigues Ribeiro, P. Jorge, A. Guerreiro
The intensity profile of a focused beam of light can exert small drift forces on particles with a few microns and even smaller, which can be used to confine or manipulate them. Optical trapping has several applications, in particular it has been adopted as a powerful tool in biology, allowing, for instance to manipulate in vivo single cells. A wide variety of optical setups have been implemented to optically trap microscopic bodies, however, the single beam trap using a tightly focused Gaussian beam continues to be the most used. Recent developments introduced an alternative to bulk optical trapping systems based on lensed optical fibers. This work presents simulations showing new designs of fiber optic and 2D waveguide tweezers based on studies of the forces acting on dielectric particles immersed in media with a distinct refractive index, which take into account the refractive index and structure of the particles.
聚焦光束的强度分布可以对几微米甚至更小的粒子施加很小的漂移力,这可以用来限制或操纵它们。光捕获有几个应用,特别是它已被用作生物学中的强大工具,例如允许在体内操纵单细胞。各种各样的光学装置已经被用于光学捕获微观物体,然而,使用紧密聚焦高斯光束的单光束陷阱仍然是最常用的。最近的发展介绍了基于透镜光纤的大块光捕获系统的替代方案。本研究基于浸没在不同折射率介质中的介电粒子所受作用力的研究,将粒子的折射率和结构考虑在内,提出了光纤和二维波导镊子的新设计模拟。
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引用次数: 4
Development of a subjective refraction simulator 主观折射模拟器的研制
S. Perches, J. Ares, M. Collados
We have developed simulation software by Matlab (MathworksInc.) with a graphical interface designed for non-expert users. This simulator allows you to complete the process of subjective refraction starting from the aberrometry of the patients and analyse the influence of different factors during the exam. In addition to explain the graphical interface and its working, we show two examples about a complete process of subjective refraction with the influence of high order aberrations and without them showing the retinal image obtained in each step of the refraction process. When the Jackson Cross-Cylinder technique is made with this software, it becomes clear the difficulty of chosen between two images when high order aberrations are present. Therefore, the variability of response during the refraction can be a problem when the examiner has to reach an adequate optical prescription.
我们已经开发了仿真软件Matlab (MathworksInc.)与图形界面设计的非专业用户。该模拟器可以让您从患者的像差测量开始,完成主观折射的过程,并分析检查过程中不同因素的影响。除了解释图形界面及其工作外,我们还展示了两个例子,关于具有高阶像差影响的主观折射的完整过程,并在没有它们的情况下显示折射过程中每个步骤获得的视网膜图像。当杰克逊交叉圆柱技术是用这个软件,它变得清晰的困难,选择两幅图像时,高阶像差存在。因此,当审查员必须达到适当的光学处方时,折射期间的响应可变性可能是一个问题。
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引用次数: 1
Extremely small-core photonic crystal fiber fusion splicing with a single-mode fiber 极小芯光子晶体光纤与单模光纤熔接
B. Tibúrcio, G. Fernandes, A. Pinto
We present a low-loss fusion splicing of a non-linear photonic-crystal fiber (NL-PCF) with a single-mode fiber (SMF), helped by an intermediate fiber, using a electric-arc splicer. We also analysed the splice loss between SMF and intermediate fiber, as a function of the electrical discharge duration, to achieve a low-loss transition between SMF and intermediate fiber, through a thermally expanded core splice (TEC). The NL-PCF has a external cladding diameter of 105 μm, a core diameter of 1.7 μm and mode-field diameter (MFD) of 1.5 μm. We also performed mechanical strength tests to verify the robustness of the splice joints obtained.
我们提出了一种低损耗的非线性光子晶体光纤(NL-PCF)与单模光纤(SMF)的融合剪接,在中间光纤的帮助下,使用电弧剪接器。我们还分析了SMF和中间光纤之间的拼接损耗,作为放电时间的函数,通过热膨胀芯拼接(TEC)实现SMF和中间光纤之间的低损耗转换。NL-PCF的外包层直径为105 μm,芯直径为1.7 μm,模场直径为1.5 μm。我们还进行了机械强度测试,以验证所获得的拼接接头的坚固性。
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引用次数: 0
Gabor transform applied to superresolution in optical systems Gabor变换在光学系统超分辨中的应用
C. Jimenez, R. Perez, C. Torres
Taking into account that the Gabor transform is the Fourier transform of the multiplication of the transfer function of a system with the Fourier transform of the input signal to the system, was developed and implemented digital and optically a system that achieves optical Gabor transform, if we consider the situation when the spectral transfer function becomes very narrow and applies to images this technique will enable one to overcome the instrumental limitations of the optical system, reaching superresolution.
考虑到Gabor变换是系统传递函数与系统输入信号的傅里叶变换的乘积的傅里叶变换,开发并实现了一个实现光学Gabor变换的数字和光学系统,如果我们考虑到谱传递函数变得非常狭窄并应用于图像的情况,该技术将使人们能够克服光学系统的仪器限制。达到超限分辨。
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引用次数: 0
System for measuring the angular response of radiometers 测量辐射计角响应的系统
L. A. Berni, W. Vilela, A. F. Beloto, Felipe Oliveira de Sena
To measure the angular response of radiometers developed in the laboratory, an automated system was assembled and characterized. The main light source is a QTH lamp of 1000W and for UV radiometers a Hg(Xe) lamp of 500W. The light beam has a useful diameter of 40 mm, a half divergence of 10mrad and the spatial uniformity is better than 97%. Errors up to 5% at large angles were estimated for misalignments of 1° in the positioning of the radiometers . In this work details of the system and results of measurements obtained with radiometers developed in the laboratory and with commercial ones are presented.
为了测量实验室研制的辐射计的角响应,组装了一个自动化系统并对其进行了表征。主光源为1000W的QTH灯,紫外线辐射计为500W的Hg(Xe)灯。光束有效直径40 mm,半发散10mrad,空间均匀度优于97%。在大角度下,对辐射计定位误差1°的估计误差可达5%。在这项工作中,详细介绍了该系统以及用实验室和商用辐射计所获得的测量结果。
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引用次数: 3
Design of a control system for interferometric fringe stabilization system with remote access 远程干涉条纹稳定系统控制系统的设计
Javier Espitia-Gómez, Luciano Ángel-Toro, D. Velásquez
Stability in a fringe pattern is a necessary condition in interferometric processes, such as holography, and not always is enough the use of passive stabilization systems, like holographic tables, in particular, when perturbations are caused by thermal or acoustic variations. For these cases, active systems are required. In this work it is presented the implementation of a control system for interferometric fringes stabilization. The interferometric arrangement characteristics are also discussed, which permits to act independently over each of the interferometer's arms by means of two piezoelectric actuators that change the length of the optical path of light that goes through, in order to perturb the system and simultaneously compensate this perturbation in real time. It is also shown that the proposed system allows evaluating the control system's performance subjected to diverse perturbations, and it is shown how remote access was given to the implemented platform.
条纹图案的稳定性是干涉测量过程(如全息)的必要条件,而被动稳定系统(如全息表)的使用并不总是足够的,特别是当扰动是由热或声变化引起的。对于这些情况,需要主动系统。本文介绍了干涉条纹稳定控制系统的实现。还讨论了干涉测量的排列特性,该特性允许通过两个压电致动器在干涉仪的每个臂上独立作用,这两个压电致动器改变通过的光路的长度,以扰动系统并同时实时补偿这种扰动。还表明,所提出的系统允许评估控制系统在各种扰动下的性能,并展示了如何远程访问所实现的平台。
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引用次数: 0
Operating principle of a high resolution ultrasonic ranging system based in a phase processing 基于相位处理的高分辨率超声测距系统的工作原理
Laura X. Chaparro, C. R. Contreras, J. Meneses
Traditionally, ultrasonic ranging sensors emit pulse trains. The distance traveled by the received signal is calculated from its delay with respect to the emitted signal. There are different strategies to encode the signal in order to determine the delay. In this paper we present a method for encoding amplitude that encodes the amplitude of a signal formed by rectangular pulse trains whose frequency is 40 kHz. The pulse amplitude is encoded in a binary manner according to a pseudorandom sequence. Owing to that the emitted signal is formed by pulse trains whose amplitude is modulated, the impulse response of the designed system generates sinusoidal pulse trains whose amplitude is variable. The proposed strategy uses the phase of signal to position temporally each pulse trains. This positioning has higher precision than the sampling time of the signal.
传统上,超声波测距传感器发射脉冲序列。接收信号行进的距离由其相对于发射信号的延迟计算。有不同的策略来编码信号,以确定延迟。本文提出了一种对频率为40khz的矩形脉冲串构成的信号的幅度进行编码的方法。脉冲幅度按照伪随机序列以二进制方式编码。由于发射信号是由幅度调制的脉冲串构成的,因此所设计系统的脉冲响应产生幅度可变的正弦脉冲串。该策略利用信号的相位对每个脉冲序列进行时域定位。这种定位比信号的采样时间具有更高的精度。
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引用次数: 2
Optical simulation of laser beam phase-shaping focusing optimization in biological tissues 生物组织中激光束相位整形聚焦优化的光学模拟
Ricardo Gomes, P. Vieira, J. Coelho
In this paper we report the development of an optical simulator that can be used in the development of methodologies for compensate/decrease the light scattering effect of most biological tissues through phase-shaping methods. In fact, scattering has long been a major limitation for the medical applications of lasers where in-depth tissues concerns due to the turbid nature of most biological media in the human body. In developing the simulator, two different approaches were followed: one using multiple identical beams directed to the same target area and the other using a phase-shaped beam. In the multiple identical beams approach (used mainly to illustrate the limiting effect of scattering on the beam’s propagation) there was no improvement in the beam focus at 1 mm compared to a single beam layout but, in phase-shaped beam approach, a 8x improvement on the radius of the beam at the same depth was achieved. The models were created using the optical design software Zemax and numerical algorithms created in Matlab programming language to shape the beam wavefront. A dedicated toolbox allowed communication between both programs. The use of the two software’s proves to be a simple and powerful solution combining the best of the two and allowing a significant potential for adapting the simulations to new systems and thus allow to assess their response and define critical engineering parameters prior to laboratorial implementation.
在本文中,我们报告了一种光学模拟器的开发,该模拟器可用于通过相位整形方法补偿/减少大多数生物组织的光散射效应。事实上,由于人体中大多数生物介质的浑浊性质,散射长期以来一直是激光医学应用的主要限制。在开发模拟器时,采用了两种不同的方法:一种是使用多个相同的光束指向相同的目标区域,另一种是使用相位形光束。在多重相同光束方法中(主要用于说明散射对光束传播的限制作用),与单光束布局相比,1mm处的光束聚焦没有改善,但在相位形光束方法中,在相同深度处的光束半径提高了8倍。利用光学设计软件Zemax和Matlab编程语言创建的数值算法对光束波前进行建模。专用工具箱允许两个程序之间的通信。事实证明,使用这两种软件是一种简单而强大的解决方案,结合了两者的优点,并允许将模拟适应新系统的巨大潜力,从而允许在实验室实施之前评估其响应并定义关键工程参数。
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引用次数: 3
Identification of retinal cells in in-vivo high resolution images 视网膜细胞在体内高分辨率图像中的识别
P. Rangel-Fonseca, A. Gómez-Vieyra, D. Malacara-hernández, Julio C. Estrada-Rico, Geovanni Hernandez-Gomez
Recent advances in the acquisition of in-vivo high resolution retinal images through the use of Adaptive Optics (AO) have allowed the identification of cellular structures such as cones and rods, in and out of the fovea, in such a way that their histological characteristics can be studied in-vivo and later compared to data obtained post-mortem. In this work, an algorithm is proposed for the detection of photoreceptors; it consists of two stages: Early Cell Detection (ECD), to detect all candidate cells, and Refinement of Cell Detection (RCD), to reduce over-detection of photoreceptors. The algorithm has been tested using synthetic and real images, the latter acquired with an Adaptive Optics Scanning Light Ophthalmoscope (AOSLO). The proposed algorithm was compared against the one developed by Li and Roorda, and both algorithms were tested on synthetic and real images, yielding similar algorithm performance on both kinds of images when they had only cones; however, the algorithm developed by Li and Roorda, when applied to real images having cones and rods, identifies photoreceptors in vascular tissue, in addition to showing low rod detection.
通过使用自适应光学(AO)获取体内高分辨率视网膜图像的最新进展,已经允许识别中央凹内外的细胞结构,如锥体和杆状体,这样就可以在体内研究它们的组织学特征,然后与死后获得的数据进行比较。在这项工作中,提出了一种检测光感受器的算法;它包括两个阶段:早期细胞检测(ECD),用于检测所有候选细胞,以及细胞检测的细化(RCD),以减少光感受器的过度检测。该算法已在合成图像和真实图像上进行了测试,后者是由自适应光学扫描光检眼镜(AOSLO)获得的。将提出的算法与Li和Roorda开发的算法进行了比较,并在合成图像和真实图像上进行了测试,当两种图像只有锥体时,算法性能相似;然而,Li和Roorda开发的算法,当应用于具有锥体和杆状体的真实图像时,除了显示低杆状体检测外,还能识别维管组织中的光感受器。
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引用次数: 0
Laser bioengineering of glass-titanium implants surface 玻璃钛植入物表面的激光生物工程
F. Lusquiños, F. Arias-González, J. Penide, J. del Val, R. Comesaña, F. Quintero, A. Riveiro, M. Boutinguiza, M. Pascual, A. Durán, J. Pou
Osseointegration is the mean challenge when surgical treatments fight against load-bearing bone diseases. Absolute bone replacement by a synthetic implant has to be completed not only from the mechanics point of view, but also from a biological approach. Suitable strength, resilience and stress distribution of titanium alloy implants are spoiled by the lack of optimal biological characteristics. The inert quality of extra low interstitial titanium alloy, which make it the most attractive metallic alloy for biomedical applications, oppose to an ideal surface with bone cell affinity, and capable to stimulate bone attachment bone growth. Diverse laser treatments have been proven as effective tools to modify surface properties, such as wettability in contact to physiological fluids, or osteoblast guided and slightly enhanced attachment. The laser surface cladding can go beyond by providing titanium alloy surfaces with osteoconduction and osteoinduction properties. In this research work, the laser radiation is used to produce bioactive glass coatings on Ti6Al4V alloy substrates. Specific silicate bioactive glass compositions has been investigated to achieve suitable surface tension and viscosity temperature behavior during processing, and to provide with the required release of bone growth gene up regulation agents in the course of resorption mediated by physiological fluids. The produced coatings and interfaces, the surface osteoconduction properties, and the chemical species release in simulated physiological fluid were characterized by scanning electron microscopy (SEM), hot stage microscopy (HSM), X-ray diffraction (XRD), X ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR).
骨整合是外科治疗对抗负重骨疾病的主要挑战。人工合成假体的绝对骨置换不仅要从力学角度出发,而且要从生物学角度出发。由于缺乏理想的生物学特性,影响了钛合金种植体的强度、回弹性和应力分布。超低间隙钛合金的惰性特性使其成为生物医学应用中最具吸引力的金属合金,而不是具有骨细胞亲和力的理想表面,能够刺激骨附着骨生长。各种激光治疗已被证明是改变表面特性的有效工具,例如与生理液体接触时的润湿性,或成骨细胞引导和轻微增强的附着。激光表面熔覆可以超越为钛合金表面提供骨传导和骨诱导性能。在本研究中,利用激光辐射在Ti6Al4V合金基底上制备生物活性玻璃涂层。研究了特定的硅酸盐生物活性玻璃成分,在加工过程中获得合适的表面张力和粘度温度行为,并在生理液体介导的吸收过程中提供所需的骨生长基因向上调节剂的释放。采用扫描电镜(SEM)、热台显微镜(HSM)、X射线衍射(XRD)、X射线荧光(XRF)和傅里叶变换红外光谱(FTIR)对制备的涂层和界面、表面骨传导性能以及化学物质在模拟生理液中的释放进行了表征。
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引用次数: 1
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Iberoamerican Meeting of Optics and the Latin American Meeting of Optics, Lasers and Their Applications
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