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71.
《Analytical letters》2012,45(4):389-404
Abstract A model is proposed which addresses the factors involved in the axial light attenuation of a coated waveguide (collector/sensor) whose polymer coating has been sensitized to ammonia. The experimental results appear to corroborate the model predictions of high sensitivity (ppb) and independence of sample flow on the collector/sensor. Concentration and relative humidity both determine the slopes of the transmission curves, the latter factor of which can be reduced to a second order effect by controlling the relative humidity in the sample holder. 相似文献
72.
Broadband and high efficiency metal multi-layer dielectric grating based on non-quarter-wave coatings as a reflective mirror
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This article deals with designing a broadband and high efficiency metal multi-layer dielectric grating (MMDG) used to compress and stretch an ultrashort laser pulse. The diffraction characteristics of the MMDG are analysed by using the rigorous coupled-wave method. The multi-layer dielectric used as the reflective mirror is made up of non- quarter-wave coatings. Taking the diffraction efficiency of the 1 order as the value of merit function, the parameters such as groove depth, residual thickness, duty cycle, and reflective mirror are optimized to obtain broadband and high diffraction efficiency. The optimized MMDG shows an ultra-broadband working spectrum with the average efficiency exceeding 97% over 160 nm wavelength centred at 1053 nm and TE polarization. The optimized MMDG should be useful for chirped pulse amplification. 相似文献
73.
Li-Yang Shao Albane Laronche Predrag Mikulic Jacques Albert 《Optics Communications》2010,283(13):2690-2694
We demonstrate a new type of fiber optic bend sensor with a hybrid structure made up of a long period grating (LPG) and a tilted fiber Bragg grating (TFBG). The sensing mechanism is based on the spectrum of power transfers between the core and cladding modes from a TFBG located downstream from a LPG. We show that the curvature of a beam can be determined by the reflected power difference between the core mode and the recoupled cladding modes. We further provide design rules for the LPG and TFBG to optimize and linearize the sensor response. In addition, the temperature cross-sensitivities of this configuration are also investigated for two different types of fiber. 相似文献
74.
Dielectric-loaded surface plasmon polariton waveguides (DLSPPWs) provide a very efficient means to localize and guide optical signal, which makes them a promising candidate for the construction of highly-integrated photonic circuits. Here, we present full 3D numerical modelling of highly efficient and compact all-optical active DLSPPW components to achieve a fully functioning active photonic circuit. 相似文献
75.
E. Hitzer 《Mathematical Methods in the Applied Sciences》2011,34(12):1421-1429
This paper discusses the geometry of kD crystal cells given by (k+ 1) points in a projective space ?n+ 1. We show how the concepts of barycentric and fractional (crystallographic) coordinates, reciprocal vectors and dual representation are related (and geometrically interpreted) in the projective geometric algebra Cl(?n+ 1) (see (Die Ausdehnungslehre von 1844 und die Geom. Anal. Teubner: Leipzig, 1894)) and in the conformal algebra Cl(?n+ 1, 1). The crystallographic notions of d‐spacing, phase angle, structure factors, conditions for Bragg reflections, and the interfacial angles of crystal planes are obtained in the same context. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
76.
77.
Suizhou Yang Ke Yang Aloke Jain Ramaswamy Nagarajan Jayant Kumar 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):938-941
A novel method for maskless micro-patterning of polymeric substrates is presented. First, an azobenzene functionalized polymer film is spin-coated on a Poly (ethylene terephthalate) (PET) sheet. Then surface relief structures are optically inscribed on the polymer film by interference of laser beams. The patterned azobenzene functionalized film is then etched in the plasma chamber such that the gratings are transferred to the PET substrate. Finally, any remaining azobenzene functionalized polymer is dissolved away using an appropriate solvent. This method of patterning can be broadly applied to a variety of flexible/polymeric substrates and the resolution is not limited by the substrate thermo-mechanical properties. 相似文献
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79.
Fabrication of gold nano‐patterns has been demonstrated employing surface relief structures created on films of an azobenzene‐functionalized polymer as templates. The surface relief templates were photoinscribed on the azopolymer films in one‐step with two laser beams. Thin layers of gold were over‐coated on the polymer templates by thermal evaporation. Gold lines of a few hundred nanometer width were successfully fabricated by pyrolyzing the azobenzene polymer. Sub‐micron gold dots were also created. The resulting gold structures exhibited the same periodicity as the polymer templates. 相似文献
80.
The orientational control of liquid crystal (LC) molecules is essential for high-quality liquid crystal displays, and the photo-induced surface relief grating (SRG) is a facile and effective non-contact process. Here, SRGs with different period and depth were prepared with a photocross-linkable organic monomer 4-propyldiphenylacetylenecarboxylic acid cinnamyl ester (PDACE), and the LC alignment induced by SRG was studied. It is found that both the surface topography and the chemical nature of the surface are responsible for the LC alignment, which is strongly dependent on the groove geometry of the gratings. Furthermore, the patterned LC cell was fabricated with the patterned SRG surface. These results demonstrate that the planar, perpendicular and patterned orientations of LC can be easily photo-controllably obtained with PDACE, which have important applications in optical devices. 相似文献