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波片相位延迟量精密测量新方法 总被引:18,自引:7,他引:11
利用旋转波片的偏振干涉技术,结合机械-光学旋光调制器对光相位的调制,通过判断方波信号的有无,可精密地确定被测定片相位延迟的数值,机械-光学旋光调制器的使用,大大简化被测样品和测试装置中四分之一波片光轴方位的调整,也显著地提高了装置测量的灵敏度和波长测量范围,对环境不作特殊控制,依据本方法建立的测试装置的相对测量误差可小于千分之五。 相似文献
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斜入射时波片相位延迟和偏振像差的精确公式 总被引:4,自引:3,他引:1
在激光技术和偏光显微镜中常常在斜入射状态下使用波片,本文提出了一个波片相位延迟和偏振像差的精确公式。这一公式对于精确计算波片的调谐曲线和偏光显微镜的偏振像差十分重要。计算表明只要适当选择晶体的方位角,波片的相位延迟和偏振光的椭圆率随入射角的改变能减少到最小。 相似文献
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红外波片相位延迟的测试方法及精度分析 总被引:8,自引:1,他引:7
通过全面分析光强随波片方位角的变化从中优化出可适用于红外波段的确定波片延迟的方法。此方法只需读取输出光强的最大值和最小值,通过简单运算得到所测波片的相位延迟。以此为理论基础,建立了一套红外波片检测系统,此系统使用元件的数量较少,操作简单,重复性好,易于得到较高的测试精度。此外,从系统光源、光学元件到接收器件等组成部分分析了整个系统中各种误差源对测试精度的影响。结果表明,该系统的检测精度与波片延迟有关,并给出其关系曲线,由该曲线可知,当所测波片的延迟大于40ο时,该系统的仪器相对误差在1%之内,对于常用1/4和1/2波片,仪器相对误差分别为0.2%和0.01%。该检测系统的测试精度在可见和近红外波段基本保持不变。 相似文献
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基于平面对称光栅反射镜系统的像差理论,根据光学元件材料折射率对成像光束波像差进行修正,将像差理论扩展到平面对称折射光学系统,使得该理论可应用于光束斜入射的折反射组合光学系统的像差计算;指出在折反射组合光学系统中考虑物像方空间折射率的关系,以及入射角方向的定义,使得波像差的计算表达式保持统一;应用扩展后的像差理论对折反射... 相似文献
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Jyh-Rou Sze An-Chi Wei Fong-Zhi Chen 《Applied Physics A: Materials Science & Processing》2010,101(1):173-178
We design three types of diffractive optical elements (DOEs) which generate pseudo-nondiffracting beams (PNDBs) in different
regions by using the conjugate gradient method. In order to analyze the influence of the tilt angles of the DOEs, the coordinate-transformation
method is used to simplify the calculation. The uniformity of the out-coupling illuminance along the optical axis is calculated.
The analyzed results show that when the tilt angle increases, the uniformity in the region [140 mm, 200 mm] has more violent
fluctuations than those in the regions [280 mm, 340 mm] and [380 mm, 520 mm]. The analyses also reveal that the uniformity
of DOEs with a longer focal length is less sensitive to the tilt angle, and some points within the PNDB region have small
variations of axial illuminance while the tilt angle increases. 相似文献
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In this paper, we present disordered layered systems in which delocalized waves with nonzero frequency can exist in the case of oblique incidence. The appearance of the delocalized waves is attributed to two factors: one is the existence of the localized modes in the systems, and the other is the phase matching condition. The conclusions are not in agreement with the traditional view, and may provide new understanding to the wave phenomena in one-dimensional disordered systems. In addition, the systems proposed here are also very useful for detecting and generating quasi-monochromatic acoustic waves. 相似文献
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I. Gutu C. Petre I. N. Mihailescu M. Taca E. Alexandrescu I. Ivanov 《Optics & Laser Technology》2002,34(5):381-388
An effective method for surface heat treatment with 10.6 μm linear polarized laser beam at oblique incidence is reported. A circular focused laser spot on the workpiece surface, simultaneously with 2.2–4 times increasing of the absorption are obtained in the 70–80° range of the incidence angle. The main element of the experimental setup is the astigmatic focusing head which focalize the laser beam into an elliptical spot of ellipticity >3 at normal incidence. At a proper incidence angle (obtained by the focusing head tilting) the focused laser spot on the work piece surface gets a circular form and p-state of polarization is achieved.We performed laser heat treatment (transformation hardening, surface remelting) of the uncoated surface, as well as the alloying and cladding processes by powder injection. An enhancement of the processing efficiency was obtained; in this way the investment and operation costs for surface treatment with CO2 laser can be significantly reduced. Several technical advantages concerning the pollution of the focusing optical components, powder jet flowing and reflected radiation by the work piece surface are obtained. 相似文献
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Silicon, germanium and indium phosphide targets are sputtered with a cesium ion beam. The energy of impact is changed from 2 keV to 10 keV and the incidence angle of bombardment is modified from 30° to 60°. Emitted matter is collected on a semi-cylindrical copper foil. Subsequently, spatially resolved thicknesses and elemental compositions of the deposit are determined by means of SIMS depth profiles. These distributions across the deposit allow us to deduce the angular distribution of emitted matter. Our experimental data show that the preferential direction as well as the spreading around this direction can be altered, with more or less efficiency, by the variation of the bombardment parameters. For the indium phosphide, we also study the elemental composition of the deposit in function of the emission angle. It shows an increasing deviation from stoichiometry with increasing emission angle. 相似文献
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针对美国布鲁克海文国家实验室(BNL)型的光阴极微波电子枪,模拟了不同分布状态的驱动激光脉冲斜入射光阴极对束流质量的影响,给出了改变注入相位和补偿线圈磁场强度对发射度的优化结果。结果表明:光斑椭圆化将会导致发射度的大幅增长,优化效果不理想;波前不同步导致的发射度增长对于纵向高斯分布的脉冲可以得到理想的优化。对于斜入射引起的光斑椭圆化和波前不同步问题给出了光学校正方法及部分测量结果。此外,模拟结果显示,对于横向均匀分布的激光脉冲,适当椭圆度的光斑比圆形光斑更有利于提高电子束质量。 相似文献
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针对美国布鲁克海文国家实验室(BNL)型的光阴极微波电子枪,模拟了不同分布状态的驱动激光脉冲斜入射光阴极对束流质量的影响,给出了改变注入相位和补偿线圈磁场强度对发射度的优化结果。结果表明:光斑椭圆化将会导致发射度的大幅增长,优化效果不理想;波前不同步导致的发射度增长对于纵向高斯分布的脉冲可以得到理想的优化。对于斜入射引起的光斑椭圆化和波前不同步问题给出了光学校正方法及部分测量结果。此外,模拟结果显示,对于横向均匀分布的激光脉冲,适当椭圆度的光斑比圆形光斑更有利于提高电子束质量。 相似文献
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Effects of oblique incidence of terahertz waves on the response of planar split-ring resonators are investigated, both experimentally and by simulation. It is found that the incident angle dependent phase delay and coupling conditions of neighboring split-ring resonator(SRR) units play important roles and greatly change both the transmission and reflection spectra for the resonant feature of linear charge oscillations. Our results show that the SRR structure-supported magnetoelectric couplings at oblique excitation are trivial and can be ignored. A highly symmetric response is found in the cross-polarization effects, which may manifest the bianisotropic properties of the SRR system but this needs further study. 相似文献