共查询到19条相似文献,搜索用时 93 毫秒
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复合树脂材料已成为重要的牙齿美容修复材料.本文利用两种布喇格光纤光栅传感器测定了口腔复合树脂材料在光固化过程中的收缩与温度演化特性.一种为普通的光纤布喇格光栅,另一种为经过了化学镀镍的光纤布喇格光栅,同时埋入复合树脂样品中,用光照射使其固化,测得光纤布喇格光栅在固化过程中温度和应力随时间的演化曲线.实验结果表明,在光固化过程中,因为聚合反应,树脂产生了强烈的收缩应力和温度变化.掌握复合树脂的光固化收缩特性和温度变化特性对不断改良材料性能以及优化口腔材料的治疗效果具有实际意义. 相似文献
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用布喇格光纤光栅传感器测定口腔复合树脂材料光固化收缩与温度演化特性 总被引:1,自引:1,他引:0
复合树脂材料已成为重要的牙齿美容修复材料.本文利用两种布喇格光纤光栅传感器测定了口腔复合树脂材料在光固化过程中的收缩与温度演化特性.一种为普通的光纤布喇格光栅,另一种为经过了化学镀镍的光纤布喇格光栅,同时埋入复合树脂样品中,用光照射使其固化,测得光纤布喇格光栅在固化过程中温度和应力随时间的演化曲线.实验结果表明,在光固化过程中,因为聚合反应,树脂产生了强烈的收缩应力和温度变化.掌握复合树脂的光固化收缩特性和温度变化特性对不断改良材料性能以及优化口腔材料的治疗效果具有实际意义. 相似文献
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研究了磁光耦合强度对磁光光纤布喇格光栅中模式转换光反射光谱特性的影响.根据磁光耦合模理论并结合光纤布喇格光栅的传播特性,数值分析了磁光光纤布喇格光栅的磁控特性,得到了3 dB带宽可调的滤波器.采用级联磁光光纤布喇格光栅构造磁控梳状滤波器,实现了40 Gbps归零数据信号的全光时钟提取仿真,分析了时钟信号的抖动性能与磁光耦合参量的关系. 相似文献
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B. Wang C.-C. Sun T.-H. Yang P. Ye J.-Y. Chang 《Applied physics. B, Lasers and optics》2001,72(6):691-696
Anisotropic self-diffraction (ASD) under Bragg mismatch has been studied. We derive a solution that can describe well the
diffraction characteristics of the anisotropic self-diffraction under Bragg mismatch. The solution is useful for estimating
the Bragg constraint when the ASD is applied to optical information processing. Both the theory and the experiment are presented.
Received: 11 July 2000 / Revised version: 2 January 2001 / Published online: 30 March 2001 相似文献
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The dependences of the spectral characteristics of reflection holograms on various parameters are investigated for the model of multilayered thin films and in the context of the Kotel'nikov theory of coupled waves. The practically important cases of the influence of the recording layer thickness shrinkage, the Bragg angle mismatch, and the recording of multicolored reflection holograms are considered. A comparative analysis of the experimental data and the results of computer modeling is made. 相似文献
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Diffraction of monochromatic light on a grating leads to the attenuation of the transmitted beam of diffraction order zero. In the case of a thick grating the diffraction efficiency, and hence the effective attenuation coefficient, is a fast-varying function of the Bragg mismatch angle. According to Kramers-Kronig theory, the transmitted beam encounters a phase shift that also depends on the mismatch angle. This phase shift is measured for holographic gratings in a photoaddressable block copolymer and compared with analytical calculations. 相似文献
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采用改进型Sagnac干涉光栅写入系统,利用532nm准带隙光曝光源和带+1/-1衍射级的相位掩模板,在两种不同直径的低损耗As_2S_3硫系玻璃光纤上刻写布喇格光栅,并研究曝光期间光栅的动态特性.实验表明,As_2S_3光纤布喇格光栅透射峰值随光纤直径的减小而增强;在曝光过程中,布喇格波长先是较快地向短波长方向移动,随着曝光时间的延长,布喇格波长缓慢地向长波长方向回复.曝光时间为800~1 000s时,在包层直径为140μm的As_2S_3光纤上获得质量良好的布喇格光栅光谱,其透射峰值可达-2.6dB,带宽为0.37nm.对As_2S_3硫系光纤纤芯的光敏性分析结果表明,折射率调制幅度和平均折射率变化随曝光时间分别可达到10-4和10-3数量级. 相似文献
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Bragg angle mismatch by tangential and radial tilts is a critical problem in holographic digital data storage. Generally,
tangential tilt can be easily compensated for in holographic digital data storage. However, radial tilt is not easily compensated
for. In this paper, we propose a new method of radial tilt compensation. The proposed method can compensate for Bragg angle
mismatch caused by radial tilt. 相似文献
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Characteristics of hydrogenated fiber Bragg gratings 总被引:1,自引:0,他引:1
C. L. Liou L. A. Wang M. C. Shih 《Applied Physics A: Materials Science & Processing》1997,64(2):191-197
By utilizing both hydrogen loading for photosensitivity enhancement and a phase
mask for holographic exposure, we have fabricated fiber Bragg grating with controllable reflectance and bandwidth. The evolution
of hydrogen diffusion into a single-mode optical fiber before exposure, and out of the fiber after exposure was characterized,
and the results were consistent with the theoretical modeling. The shifting of Bragg wavelength and thermal reliability were
found related to the hydrogen behavior inside the fiber. One solution to prevent Bragg wavelength from drifting after the
grating was formed and hence to increase the grating's reliability was to anneal it so that the residual hydrogen was forced
out of the optical fiber in a short time.
Received: 12 June 1996/Accepted: 17 June 1996 相似文献
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Suzanne T. Mcdaniel 《Waves in Random and Complex Media》1996,6(3):229-249
A rigorous theory of backscattering from slightly rough, statistically non-stationary surfaces is developed. The development proceeds through the application of two ensemble averages: the first is applied to all realizations of the surface having fixed non-stationary features, and the second over all non-stationary surface characteristics. The resulting theory is applied to acoustic sea-floor reverberation, where it is found that non-stationarity must be assumed to obtain agreement with observed reverberation fluctuations. The analysis is further extended to the time domain where it is demonstrated that, for Bragg scatter, no reduction in the predicted fluctuations occurs for frequency diverse waveforms, thus providing a method of differentiating Bragg scatter from other non-resonant scattering processes. 相似文献
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将光纤光栅的傅里叶模式耦合理论应用于光纤布拉格光栅型全光纤声光调制器的理论分析中. 与现有的分析方法相比, 该模型算法简单、 求解容易, 能够快速有效地获得调制器的传输特性. 基于该模型, 理论分析了超声波频率及声致应变幅度对调制器特性的影响. 仿真结果表明, 该调制器反射谱的主反射峰与次反射峰的波长间隔与超声波频率成正比, 反射峰的反射率随着声致应变幅度的改变而发生周期性的变化. 另外, 在同一声致应变幅度下, 低频超声波调制的光栅反射中存在更多的次反射, 光栅反射能量的周期性变化更加明显. 实验中, 使用频率为885.5 kHz的超声波对光纤布拉格光栅进行调制. 实验结果与仿真结果相一致. 相似文献