共查询到19条相似文献,搜索用时 109 毫秒
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采用镀K9玻璃薄膜方法来解决离子交换掺铒磷酸盐玻璃波导表面的侵蚀问题,对K9玻璃薄膜的厚度进行了优化研究。测量分析了样品的荧光光谱和荧光寿命,采用光学显微镜和棱镜耦合技术对不同K9玻璃薄膜厚度下制备波导的表面形貌和导光特性进行了表征和测试。结果表明,与掺铒磷酸盐玻璃原材料相比,镀K9玻璃薄膜后荧光光谱保持不变,荧光寿命稍有下降(约0.2 ms);K9玻璃薄膜的厚度在60~80 nm的范围内保护效果最佳。为下一步制备掺铒有源玻璃光波导器件奠定了良好的实验基础。 相似文献
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继文献[1]之后,我们又用激光外差干涉仪测量了K9玻璃低压(0~3.5kg)下的双折射率,发现△~n_o~F和△~n_o~F呈不同的变化规律,这个现象是由样品内部应力分布的不均匀所导致的,反映了实际天文透镜自重引起的双折射率变化。 相似文献
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用伪色差概念和PW方法设计双折射透镜初始结构 总被引:2,自引:0,他引:2
双焦点干涉显微镜因其高稳定性和高分辨率的特点而受到重视,其核心元件双折射透镜由一片双折射晶体和一片光学玻璃胶合而成。为了双折射透镜的设计工作方便,引入“伪色差”概念,定义“伪色散倒数”,从而可以借用现有的初级像差理论,运用PW方法,给出满足不同设计要求的三种双折射晶体和三种玻璃配对的双胶合透镜的初始结构表格,在不同的应用场合,可用OSLO软件进行像差计算和优化设计,取得需要的结果。为了便于评价这种特定的结构,定义紧凑因子7作为一个评价指标。给出采用方解石和ZF1作材料的设计实例,该设计结构紧凑(γ=0.25)。 相似文献
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We study the intensity point spread function (IPSF) of a uniaxial birefringent lens sandwiched between two linear polarizers under broadband illumination having flat-top spectral profile. The optic axis of the birefringent crystal is perpendicular to the lens axis. For monochromatic input illumination, a low-power birefringent lens offers enhanced resolution under parallel-polarizers configuration and apodization under crossed-polarizers configuration with a single focus as well. At a relatively high value of birefringence parameter, the proposed system behaves as a double-focus lens. The present communication uses a novel technique to study the effect of polychromatic illumination on the imaging characteristics of birefringent lenses. The studies reveal that the imaging characteristics of the low-power birefrigent lens does not deteriorate considerably under polychromatic illumination. However, for a polychromatic beam with large bandwidth, the imaging behavior of the system having high birefringence parameter deviates appreciably from that under strictly monochromatic illumination. The said system even loses its inherent bi-focal nature due to depolarization of polarized polychromatic light upon passage through the birefringent crystal. 相似文献
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在正交偏光系统中置入一天然解理的双折射晶块和会聚透镜,可获得清晰的偏振光干涉分布图样。该文利用双折射晶体的偏振分束原理对干涉图样的产生和条纹分布进行具体的分析和计算。 相似文献
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制作铊玻璃自聚焦透镜的两步离子交换工艺分析 总被引:3,自引:1,他引:2
本文分析了用一次离子交换工艺制备的自聚焦透镜的径向折射率分布规律,讨论了所能获得的最佳分布工艺条件。在此基础上提出了两步离子交换的新方法。计算表明用两步离子交换工艺制备的自聚焦透镜的折射率分布可以更接近理想分布. 相似文献
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根据已建立的理论模型,计算得到了K9玻璃受脉冲CO_2激光辐照时产生的热应力分布,研究了热应力的时间特征,在分析样品尺寸对损伤结果影响的基础上,提出了K9玻璃抗激光损伤的最佳半径。结果表明:K9玻璃产生的热应力损伤主要由环向应力控制,热应力以热冲击波的形式在样品内传播,大小随时间变化而来回振荡,且激光脉冲结束后比激光作用时间内产生的热应力要大。这说明若样品在激光加热期间产生的热应力不足以造成材料破坏,则有可能会在其后的冷却过程中产生更大的热应力,材料将会在冷却过程中发生破裂。根据样品参数对损伤结果的影响,进一步验证了K9玻璃抗激光损伤最佳半径的通用性。 相似文献
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Yanhua Luo Zengchang Li Ru Chen Qijin Zhang Gangding Peng Gang Zou Bing Zhu 《Optics Communications》2009,282(12):2348-2353
Based on the photoinduced birefringence in azo materials, the model of the birefringent long period fiber gratings (BLPFGs) has been proposed and the transmission of such birefringent fiber gratings was further simulated by the coupled mode theory. In order to obtain the optimum condition for making birefringent azopolymer optical fiber (APOF) gratings the photoinduced birefringence of azo dye and methyl methacrylate (MMA) copolymers was systematically studied. After photosensitivity study of azo samples, using Teflon technique, azo dye containing single mode polymer optical fiber (POF) was fabricated. Finally, BLPFGs can be fabricated in azopolymer fiber using polarized 532 nm laser. A 120 μm LPFG with a 50% duty cycle has been successfully written within the core of the fiber with 532 nm laser by an amplitude mask method. Under polarized microphotography, the grating was observed when the optical axis was set at 45° with the direction of the first polarizing lens of the polarization microscope. 相似文献
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基于传热学理论, 利用有限元法对KrF准分子激光辐照K9玻璃样品中的热力效应进行了数值分析, 并比较了脉冲数目和重频对损伤效果的影响。研究表明, 较低的准分子激光能量就能够使K9玻璃在表面和体内产生热应力损伤, 热应力损伤在光斑区域内主要由压缩热应力控制, 在光斑边缘和材料内部则主要由拉伸热应力控制。在激光脉冲结束时刻, 产生的温度和热应力最大, 且热应力以热冲击波的形式在材料内传播, 随时间变化而来回振荡, 逐渐减弱。这种热应力的反复冲击会对材料产生持续的损伤增长效应, 增加了材料的损伤时间, 并使材料更容易断裂。脉冲数目和重复频率对损伤效果有着较大影响, 在高重复频率下, 损伤累积效应明显。 相似文献
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Polychromatic or white-light optical transfer function (OTF) is put forward as a criterion to evaluate the performance of a uniaxial birefringent lens sandwiched between two linear polarizers. The optic axis of the birefringent crystal is perpendicular to the lens axis. The results show that the same system may be adapted for both enhanced resolution and apodization just by rotating any of the polarizers included in the system even under broadband illumination. The proposed system may also be exploited for image processing applications under polychromatic input illumination. 相似文献