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Cs^+-K^+ ion exchanges are performed on z-cut KTiOPO4 crystals with chromium coating covered. The temperature of ion exchange is 430℃, and the time range from 15min to 30min. The dark mode spectra of the samples are measured by the prism coupling method. The channel structures on the samples are observed by a microscope and the near field pattern of the channel waveguides are measured by the end-fire coupling method. The refractive index of the samples increases and the increments at surface are modulated due to the existence of Cr film. In the region covered by Cr film, the refractive index of the samples at the surface increases dramatically in a shallow layer. The results of energy dispersive x-ray spectra indicate that in the region covered with Cr film, Cr ions participate in the ion exchange process, and enhance the refractive index. The results may provide a possibility that achieves index enhancement and Cr doping synchronically. 相似文献
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光纤布拉格光栅在通信和传感领域具有广泛的应用。利用光纤布拉格光栅中心波长的偏移,可以测量温度和应变等多种物理量,但必须解决光栅对温度和应变的交叉敏感问题。该文简要分析了光纤光栅作为传感器的基本原理及其优点,设计了利用参考光栅法分离温度影响以及利用掺铒光纤的自发发射放大特性分离温度影响的2种应变测量方法。最后,介绍了一种利用倾斜光纤光栅的主模和边模对布拉格光栅中心波长的偏移进行解调的方法,该方法成功地分离了温度对应变测量的影响。 相似文献
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研究了人体劳宫穴及其周边的非穴位组织受不同功率的半导体激光(波长为808 nm功率分别为20,50,100 mW)照射前后在400~1 000 nm光谱范围的反射光谱特征及其差异.实验采用带积分球附件的AvaSpec-2048光纤光谱仪测量系统获取劳宫穴和非穴位组织的反射光谱.结果表明,在半导体激光照射前,劳宫穴与非穴位的反射光谱的光谱轮廓相似,波谷均出现在423,544,577,980 nm处,劳宫穴和非穴位在对应波谷的反射率值分别为17.1%,26.1%,25.9%,35.0%和17.1%,27.6%,28.1%,36.5%.在475~1 000 nm,合谷穴的反射率比非穴位小.分别经过20,50和100 mW不同功率的半导体激光照射后,劳宫穴反射率较照射前明显下降,并且随着照射功率增大,反射率减小的幅度越大.而非穴位组织经过不同功率的半导体激光照射后反射率较照射前稍有下降,但远不及劳宫穴下降明显.由此可见劳宫穴与非穴位的反射光谱存在差异,并且劳宫穴对半导体激光照射的刺激比非穴位更敏感. 相似文献
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Second-harmonic generation as a DNA malignancy indicator of prostate glandular epithelial cells 下载免费PDF全文
This paper first demonstrates second-harmonic generation
(SHG) in the intact cell nucleus, which acts as an optical indicator
of DNA malignancy in prostate glandular epithelial cells. Within a
scanning region of $2.7~\mu$m$\times 2.7~\mu$m in cell nuclei, SHG
signals produced from benign prostatic hyperplasia (BPH) and
prostate carcinoma (PC) tissues (mouse model C57BL/6) have been
investigated. Statistical analyses ($t$ test) of a total of 405
measurements (204 nuclei from BPH and 201 nuclei from PC) show that
SHG signals from BPH and PC have a distinct difference ($p < 0.05)$,
suggesting a potential optical method of revealing very early malignancy
in prostate glandular epithelial cells based upon induced
biochemical and/or biophysical modifications in DNA. 相似文献
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In this Letter,we fabricate integrated metasurface of encoded dynamic phases and experimentally generate nonconventional Kagome-type lattices of no-second-order phase vortices.The thin metasurface acts analogous to an integration of three conventional optical elements,i.e.,six pinholes located at the vertices of two concentric regular triangles of size ratio 1:2,six transparent discs of different thicknesses to introduce a total phase shift difference of 6π,and a Fourier lens with a focal length in the micro-scale.A Kagome lattice with the required vortex distribution is realized at the"focal"plane of the metasurface under illumination of the plane wave. 相似文献