共查询到20条相似文献,搜索用时 109 毫秒
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We present a new algorithm for wide-angle propagation through a general class of optical-waveguide structures defined by dielectric interfaces that may be slanted with respect to the direction of propagation. No regularity of the structure shapes is assumed, no coordinate transformations are employed, and the movement of each grid point between propagation steps is arbitrary within modest angular limitations. When used with an appropriate grid-generation algorithm, this method allows the modeling of an extremely wide variety of high-index-contrast waveguide structures, including meanders and tapers, with good phase accuracy and energy conservation. 相似文献
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《III》2003,16(8):28
JPSA Laser’s new Fly’s Eye Beam Homogenizer converts the characteristically non-uniform beam of a UV Excimer laser into a homogeneous beam with 95% uniformity while utilizing >80% of the laser power. This long working distance single element array easily adapts to most commercial excimer lasers, and offers optimum price/performance ratio (single element for lowest cost and lowest beam loss). The JPSA Fly’s Eye Beam Homogenizer’s long working distance — typically between 1–2 meters — provides a beam size ranging from 8mm to 1.5cm. It is easily re-imaged due to the long working distance and slow optical F-number.Excimer laser beams are not perfectly uniform in intensity over the area of the beam and therefore only a portion of the area of the beam is usable for high-uniformity materials processing. In some cases, only the most uniform section or “filet” of the beam will be selected for use, and the non-uniform section of the laser beam will be discarded. Due to the premium price associated with UV photons, high beam utilisation in many cases is a key economic factor. Beam shaping optics and beam homogenisers can be employed to shape the beam and simultaneously make the laser energy uniform so that the maximum amount of the available laser power can be used. The resultant uniform, large area beam can then be subdivided using near-field imaging to project complex patterns onto a part or make simultaneous multiple laser ablations, a key advantage of UV Excimer lasers.Visit www.three-fives.com for the latest advanced semiconductor industry news 相似文献
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本文设计出了一种既能产生针状波束又能产生扇形波束的新型面天线,该天线的增益和方向图通过理论计算计算出来。本文设计实例中的面天线的针状波束的E、H平面的半功率宽度分别为2.320、2.240,而扇形波束的E、H平面的半功率宽度分别为2.010,6.40。 相似文献
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时间监控离子束溅射沉积倍频波长分离膜 总被引:1,自引:0,他引:1
采用双离子束溅射技术、时间控厚方式制备波长532 nm绿光激光器用倍频波长分离膜.针对制备过程中产生的半波孔现象,在简单分析形成原因的基础上,采用分组厚度优化方式调整膜层厚度,从而制备出无半波孔的高品质倍频波长分离膜.为时间监控制备非规整膜系的厚度修正提供了一种切实可行的办法. 相似文献
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《Microwave Theory and Techniques》1972,20(9):608-613
Experimental tests on a new type of beam waveguide constituted by a series of equispaced dielectric frames are described. Field-pattern and power-loss measurements have been performed on short-circuited sections of the waveguide working at 10 GHz and on the 37-GHz prototype constituted by Teflon square frames. In comparison with the more common iris and lens beam waveguides, it presents advantages concerning diffraction, reflection, and dissipation losses. In addition, it is lightweight and compact. The experimental results confirm these advantages, along with a low sensitivity to assembling and constructive imperfections. Design criteria are suggested as a result of the optimization for the lowest losses obtained through numerical computations performed on the equivalent open resonator. 相似文献
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非傍轴厄米-正弦-高斯光束的特性 总被引:1,自引:0,他引:1
为了研究厄米-正弦-高斯(HSiG)光束在非傍轴情形下受参量影响的特性,基于光强二阶矩理论,经过一系列复杂的数学计算,得出了非傍轴厄米-正弦-高斯光束的远场发散角、束腰宽度以及光束传输因子的解析式,并通过数值模拟,得到了它们与离心参量的关系。结果表明,在束腰宽度与波长比取值逐渐减小时,随着离心参量趋于0,当阶数为奇数和偶数时.发散角分别趋于63.435°和73.898°。束腰宽度和光束传输因子随参量的增加呈现较大的起伏,非傍轴情形下的光束传输因子取值与傍轴情况有很大的不同,其受参量影响不仅可以小于1,甚至趋于0。 相似文献
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环形障碍物后的无衍射光重建产生局域空心光束 总被引:4,自引:0,他引:4
利用Hankel波理论和几何光学原理对无衍射光经环形障碍物的重建过程进行分析,结果表明轴棱锥产生的无衍射光是由从轴棱锥出射的两列Hankel波的叠加而形成的,并用Zemax软件对无衍射光经环形障碍物的过程进行光线仿真,模拟了环形障碍物后的轴上不同位置处的截面光强图,研究了局域空心光尺寸与环形障碍物参数之间的关系。并通过实验进行验证,实验中利用轴棱锥输出无衍射光,且在最大无衍射距离内放置环形障碍物,用CCD系统记录无衍射光经环形障碍物后的光强变化,实验和仿真结果基本吻合。仿真和实验结果均表明无衍射光束经环形障碍物后会重建并能产生中心光强为零的局域空心光束(Bottle beam),在光镊和光学微操作等方面具有潜在的应用价值。 相似文献
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《光机电信息》2007,24(5):58-59
PALM (Positioning and Ablation with Laser Microbeams) Microlaser Technologies GmbH, a subsidiary of Carl Zeiss MicroImaging GmbH, has unveiled the PALM MicroBeam laser microdissection system, the only instrument capable of simultaneous microdissection fluorescence extended focus. visualization and under mnltichannel illumination and extended focus. 相似文献
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《Microwave Theory and Techniques》1964,12(4):445-453
In this paper a type of beam waveguide which uses appropriately shaped metal reflectors instead of dielectric lenses as the phase correcting devices is described. A theory has been developed which, subject to certain restrictions, describes the modes of this type of beam waveguide and predicts a loss of the order of 0.01 db per iteration. A reflecting beam waveguide comprising eight aluminum reflectors has been investigated at a wavelength of 4 millimeters. The measured loss per iteration is approximately 0.015 db which is in good agreement with the theoretical value. The cross-sectional electric field distribution has also been measured and found to be in satisfactory agreement with the theory. It is shown that the reflecting beam waveguide is a practical system for the transmission of power at submillimeter wavelengths. 相似文献
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