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A wide-band(1530-1610 nm)and high efficient double-pass discrete Raman amplifier is reported.In this Raman amplifier,by using a one-end gilded fiber as the broadband reflector,signals and multi-pump are both reflected to propagate through the gain fiber for a second time.An increase in net gain of more than 150% has been achieved compared with that in the typical co-pumped Raman amplifier.The advantages of this proposed new configuration have been experimentally studied by comparing with the recently existing Raman amplifier configurations. 相似文献
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The linear and nonlinear fluorescence spectra of 5-(9-anthryl)-3-(4-nitrophenyl)-1-phenyl-2-pyrazoline (ANPP) have been studied in different polarity solvents.The linear fluorescence spectrum of ANPP has two emission bands originating from the anthryl and pyrazoline moieties of ANPP on excitation at 355nm.The nonlinear two-photon and three-photon fluorescence from these two moieties are observed simultaneously when ANPP is excited at 1064 nm due to the proximity of the absorption bands of these two moieties to λ/3 and λ/2 of the exciting wavelength.The similar spectrum structure indicates that the nonlinear and linear fluorescence originates from the same relaxation process. 相似文献
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One-dimensional photonic crystals with two or more structural defects are studied. We observed an interesting characteristic of transmission band structure of photonic crystals with defects using the transmission-matrix-method simulation. The transmission states in the wide photonlc band gap caused by defects reveal degeneracy and split in certain conditions. Every split state is contributed by coupling of all defects in a photonic crystal.Using the tight-binding method, we obtain an approximate analytic expression for the split frequency of photonic crystals with two structural defects. 相似文献
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聚对苯撑亚乙烯/SiO2块状溶胶-凝胶非线性光学材料的研究 总被引:2,自引:0,他引:2
我们制作了一种由π-共轭聚合物聚对苯撑亚乙烯(PPV)均匀掺杂SiO2的块状溶胶-凝胶材料,该材料具有良好的光学品质和光学加工性能。通过扫描隧道显微镜(STM),紫外-可见吸收光谱和付氏红外光谱(FTIR)等方法研究了它的非线性光学特性。在对材料进行的光学两波耦合实验中,观察到了非对称能量耦合现象,并对此进行了分析。从吸光度和两波耦合衍射效率两方面对比了含PMMA和不含PMMA的两批不同掺杂浓度的PPV/SiO2 sol-gel材料的不同特性。 相似文献
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Independent Modulation of Omnidirectional Defect Modes in Single-Negative Materials Photonic Crystal with Multiple Defects 下载免费PDF全文
Single-negative materials based on photonic crystal with multiple defect layers are designed and the free modulation of defect modes is studied. The results show that the multi-defect structure can avoid the interference between the defect states. Therefore, the designed double defect modes in the zero effective-phase gap can be adjusted independently by changing the thickness of different defect layers. In addition, the two tunable defect modes have the omnidirectional characteristics. This multi-defect structure with above-mentioned two advantages has potential applications in modern optical devices such as tunable omnidirectional filters. 相似文献
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Strong second-order nonlinear effect of ZnO nanowires on a silicon wafer are demonstrated by using the hyper- Rayleigh scattering (FIRS) measurement. The large nonlinear effect can be attributed to the following two factors: (1) the large total dipole moment caused by high surface defect density and electrostatic potential gradient, (2) coherent effect due to high crystal quality of single nanowire. Moreover, the second-order nonlinear effect is found to become weaker when the chip is put into organic solvent due to modification of surface defect caused by organic molecules. The variation of second-order signal in the solvent indicated the potential applications of ZnO nanowires as a sensor-on-chip (SoC). 相似文献