共查询到16条相似文献,搜索用时 171 毫秒
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根据麦克斯韦基本方程组,推导了描述二元光栅衍射特性的矢量理论分析方法--严格的耦合波方法,给出了TE、TM 两种偏振模式入射下的耦合波方程。应用该方法对二元位相光栅的衍射特性进行了分析,验证了该方法的收敛性及准确性。讨论了光栅周期、光栅深度、入射波入射角度等参数对光栅衍射特性的影响。 相似文献
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研究了制备闪耀凹面光栅的离子束刻蚀工艺,提出了用“解析分区法”设计闪耀凹面光栅的衍射效率.该方法能通过确定离子束入射角,在实验前定量给出平行离子束刻蚀后光栅衍射效率的设计结果.经过理论设计计算出所需波长衍射效率较高的凹面闪耀光栅中心闪耀角,利用刻蚀模拟软件BLAZING计算出离子束刻蚀参数及光刻胶掩模参数;以计算结果为依据,利用全息-离子束刻蚀工艺制作出尺寸为45 mm×40 mm2,曲率半径为224 mm的凹面闪耀光栅,其中心闪耀角约为9.21°,峰值衍射效率为54.8%@300 nm,250 nm处衍射效率为50%,与“解析分区法”计算结果符合较好.实验结果表明,利用“解析分区法”进行凹面闪耀光栅衍射效率设计的方法简单易行,能够有效指导平行离子束刻蚀闪耀凹面光栅工艺,完成高衍射效率凹面闪耀光栅的制作. 相似文献
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通过刻划工艺控制光栅槽形零级面宽度,使-1级和0级衍射效率同时达到期望值是激光器调谐光栅研制中的技术难题。基于光栅电磁场理论,利用光栅非异常区入射波长与光栅周期之比λ/d≈1.414附近较宽波段范围内TM偏振波的衍射效率变化梯度小,而且同一波长的衍射效率随闪耀角增大呈单调递增或随槽顶角增大呈单调递减趋势的特性,给出了-1级振荡0级输出激光器调谐光栅的全三角槽形模型及设计方法。该方法用常规三角槽形光栅即可实现任意比值的-1级与0级衍射能量分布,避免了以往通过控制类梯形槽形零级面宽度来制作此类光栅的工艺不确定性,降低了制作难度。应用该模型设计并制作了-1级衍射效率为65%的0级输出激光器调谐光栅,其在10.6μm处的衍射效率误差为0.6%。该方法还适用于-1级振荡-1级输出激光器调谐光栅的设计,实现了两类激光器谐振光栅在设计方法以及制作工艺上的统一。 相似文献
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在有限电导率光栅的微分理论中引入校正傅里叶展开方法,改善了计算收敛性。运用改进后的微分理论对软X射线波段掠入射金属光栅的闪耀特性做了数值分析,通过详细考察三角槽形、正弦槽形和矩形镀金光栅的软X射线-1级衍射效率对光栅结构参数和入射光状态参数的响应程度,给出了一种在使用和制作工艺上都能够接受的光栅技术指标。结果表明,作为闪耀波长为10.33 nm的软X射线波段掠入射镀金光栅,采用81°入射的刻线密度为1 200 l/mm,倾斜角为2°,顶角大于120°的三角槽形光栅较为合适,其效率可达到50%以上。同时,得到了一些优化软X射线波段掠入射金属光栅设计的新结论。 相似文献
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基于有限电导率光栅的微分理论,对工作在紫外光区的全息正弦光栅和三角槽形光栅的衍射效率做了数值计算。给出了紫外全息光栅的闪耀特性分布曲线并分析了三角槽形光栅顶角大小对衍射效率的影响。 相似文献
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宽波段金属光栅设计中闪耀波长对光栅异常的补偿效应 总被引:3,自引:3,他引:0
给出适用性强、工艺上易于实现的单闪耀面宽波段金属光栅设计新方法。基于Rayleigh异常和共振异常两种不同的光栅异常机理,分别讨论了它们出现的条件,在光栅电磁场理论的基础上,数值分析了TE波、TM波闪耀波长的分布规律,发现了闪耀波长与光栅异常、光栅光谱范围的关系,提出了用TM波第一闪耀波长补偿Rayleigh异常或共振异常实现制作宽波段金属光栅的设计思想。同时,指出了TM波第一闪耀波长对Rayleigh异常的补偿效应,只是它对共振异常的补偿效应的极限情况。给出了将补偿效应应用于紫外可见分光光度计、近红外分光光度计和红外分光光度计用不同刻线密度宽波段金属光栅的设计实例。补偿效应法无论在理论设计上还是在工艺实现上都要优于传统的宽波段金属光栅设计方法,它可以使得用于各个波段上的宽波段金属光栅衍射效率都在40%以上。 相似文献
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Chien-Hung Liu Wen-Yuh Jywe Chao-Kwai Chen 《The International Journal of Advanced Manufacturing Technology》2005,26(7-8):808-813
A simple measurement system has been developed and implemented for the simultaneous measurement of pitch, yaw and roll of
the moving axes of a linear stage. This developed system is based on the principle of the diffractive theorem and optical
triangulation. It is composed of a laser source, two quadrant detectors and a diffracting grating. The diffraction grating
mounted on the moving axes of a stage reflects an incident laser beam into several diffractive rays and two quadrant detectors
are set up for detecting the position of ±1st-order diffraction rays. When the diffraction grating moves, the locations where
the diffractive beams are generated change and also the positions of the spots on two quadrant detectors. According to the
relationship between the three angular motions of a moving stage and the output coordinates of two quadrant detectors, an
inverse algorithm is used to solve these pitch, yaw and roll angular errors through a kinematic analysis . 相似文献
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Katayama K Uchimura H Sakakibara H Kikutani Y Kitamori T 《The Review of scientific instruments》2007,78(8):083101
The near-field heterodyne grating (NF-HDG) method was applied to flow rate measurements in a microtube. The NF-HDG method is a newly developed optical technique based on photothermal effects. In this technique, pump light is shone on a transmission grating in front of a fluid channel and the inside liquid is heated with a pattern of the grating due to the Talbot effect. Another probe light is similarly shone on the same place as the pump light, and the diffraction by the transmission grating (reference) and the diffraction by the temporally generated thermal grating inside the fluid channel (signal) are mixed and detected (heterodyne detection). Theoretical analysis reveals that the dependence of the heterodyne signal intensity on the flow rate originates from the change in the heterodyne phase difference between the signal and reference, and the experimentally obtained calibration curves can be fitted with the theoretically predicted function. Furthermore, the optical setup was optimized based on the theoretical analysis of the Talbot effect. Flow rates of the order of nl/min were quantitatively measured, and the detection limit of the flow rate was 17 nl/min. 相似文献
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A technique is described which permits the simultaneous acquisition of multiple fluorescent emission and/or absorption spectra from discrete regions of a specimen under microscopic observation. The instrument consists of a modified inverted microscope, an optical diffraction grating, a silicon intensified target (SIT) camera, and a digital video image processor. Observation of the zero diffraction order of the grating with the SIT camera permits an optical slice of the specimen to be selected by positioning the region of interest over the entrance slit of the grating housing. To obtain the spectral characteristics of this optical slice, the grating is rotated to impinge the first order diffraction on the camera. The video image of this first order diffraction maintains spatial integrity along the slit's long axis and provides spectral dispersion on the perpendicular axis. Thus, each of the horizontal video lines along the long axis of the slit represents a spectral analysis of the corresponding spatial location within the specimen. The spectral resolution (0.2 nm/channel) of each video line is determined by the resolution of the camera system in conjunction with the resolution of the grating. The image processing system acquires and processes all 500 spectra in 33 ms and permits the accurate localization of the source of each spectrum in the slice. This type of topological spectral analysis permits the determination of both spatial and spectral characteristics of intrinsic or extrinsic chromophores within the specimen. In addition, this technique permits the detection of and the possible correction for photobleaching, light scattering and image plane effects. The application of this technique to the study of single cells is discussed and an example of the technique in determining the fluorescence spectra of acridine orange within the nucleus of an intact mammalian blastocyst is described. 相似文献