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201.
202.
Guoping Dong 《Optics Communications》2007,274(2):466-470
Transparent glass ceramics were prepared by heat treating of the as-prepared 80GeS2 · 10Ga2S3 · 10CdI2 glass at 370 °C (Tg + 15 °C) for 72 h (labeled as GGCd10-370). The existence of α-CdGa2S4 crystal in GGCd10-370 glass ceramics has been testified by XRD and Raman spectroscopy. Using the typical Maker fringe technique, SHG was observed in the original transparent GGCd10-370 glass ceramics successfully, which is mainly ascribed to the α-CdGa2S4 nonlinear optical microcrystal. And the SH intensity is almost 0.8 times larger than that of the standard quartz reference. It can be also deduced that the thickness of crystalline layer is a little larger than the coherent length, lc ≈ 2.7 μm. 相似文献
203.
研究了置于空气中的含缺陷的一维非线性光子晶体中二次谐波的产生.由于反射的二次谐波很强而不能忽略,缓变振幅近似在系统中是不适用的.本文提出了一种不采用缓变振幅近似来处理二次谐波产生问题的方法,并应用这种方法计算相关的二次谐波转换效率.结果表明:随着入射波角度的增加,缺陷模对应的波长将变短,并且通过调整基频波入射的角度,可以产生宽带宽并且高转换效率的二次谐波.这个方法适用于任何一维非均匀系统,可以简单方便地计算出二次谐波转换效率. 相似文献
204.
Er3+ doped ZnO-CaO-Al2O3 nano-composite phosphor has been synthesized through combustion method and its emission and harmonic generation properties have been studied. The X-ray diffraction and thermal analysis techniques have been used to prove the dual phase (ZnO and CaO-Al2O3) nature of the phosphor. The phosphor has shown up-conversion emission on near-infra-red (976 nm) excitation and down-conversion emission on 355 nm excitation in presence of Er3+ and thus behaves as a dual mode phosphor. On excitation with 976 nm diode laser, material shows color tunability (calcination of composite material at different temperatures). Formation of ZnO nanocrystals on heat treatment of as-synthesized sample has shown its characteristic emission at 388 nm and also the energy transfer from ZnO to Er3+ ions. The low temperature emission measurements have been carried out and the results have been discussed. Phosphor has shown strong second harmonic generation (SHG) at 532 nm on 1064 nm and at 266 nm on 532 nm excitation. 相似文献
205.
We have performed the studies of photoinduced second harmonic generation in the ZnO nanorods doped by Thulium with different content (0.1; 0.2;0.5% of Tm). The illumination was performed with the Er:glass laser emitting at 1540 nm wavelength of the 10 ns laser and the output second harmonic generation (SHG) was studied. The AFM data analysis was performed. The role of the rare earth Tm ions on the morphology and the optically stimulated SHG is discussed. The SHG yield was found to be strongly dependent on Thulium content and Root Mean Square roughness of the studied layers. 相似文献
206.
Two homochiral enantiomorphic 3D coordination polymers: (D-HAPA)2[Cd2Cs(D- HAPA)(m-BDC)4]'(EtOH) (1D) and (L-HAPA)2[Cd2Cs(L-HAPA)(m-BDC)a]'(EtOH) (1L) (APA = 2-amino-l-propanol, m-H2BDC = 1,3-benzenedicarboxylate), have been assembled solvothermally respectively with the induction of enantiomorphic organic small molecules (D,L-APA). 1L and 1I) crystallize in chiral space group P21 with Flack parameters of-0.012(13) and -0.07(3), respectively, and have been characterized by satisfactory elemental analysis, FT-IR spectra, CD-spectra and single-crystal X-ray diffraction. They both exhibit sqp topological net, purple fluorescence and SHG activity. 相似文献
207.
Surface second-harmonic generation based on periodically poled LiNbO3 nonlinear optical crystal 下载免费PDF全文
We have generated a second-harmonic generation(SHG) of a Q-switched microchip Nd:YAG laser on the surface of a periodically poled LiNbO3(PPLN) nonlinear crystal near the grazing incidence angle.Three individual SHG waves as transmitted homogeneous,inhomogeneous and reflected radiations have been generated and their intensities are measured and characterized within a desirable range of about 10 different incidence angles of the Nd:YAG laser as pump source on the PPLN surface.The basic of surface nonlinear radiation is also investigated and similar results are calculated and extracted from the theory.Comparison between calculated and measured data shows that they are in good agreement with each other. 相似文献
208.
209.
T. Vijayakumar I. Hubert Joe C. P. Reghunadhan Nair Mojca Jazbinsek V. S. Jayakumar 《Journal of Raman spectroscopy : JRS》2009,40(1):52-63
The optimized geometry and structural features of the most prospective electro‐optic crystal 4‐(N,N‐dimethylamino)‐N‐methyl‐4′‐toluene sulfonate (DAST), and the vibrational spectral investigations have been comprehensively described with the near infrared Fourier transform (NIR FT) Raman and Fourier transform infrared (FT‐IR) spectra supported by the density functional theoretical (DFT) computations to elucidate the contribution of vibrational modes to the linear electro‐optic (LEO) effect. Mulliken population analysis and natural bond orbital (NBO) analysis have also been carried out to analyze the effects of intramolecular charge transfer (ICT), intramolecular hydrogen bonding and hyperconjugative interactions on the geometries. The influence of CT interaction between the phenyl ring and the dimethylamino group of the nonlinear optical (NLO) chromophore on the endocyclic and exocyclic angles, and the electronic effects such as hyperconjugation and back‐donation on the methyl hydrogen atoms have been examined. The concurrent intense activation of Raman and IR activities of the effective conjugation vibrational coordinate, which significantly contributes to the LEO effect resulting from the strong electron–phonon (e/ph) coupling, has been analyzed in detail. The effects of frontier orbitals, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), transition of electron density (ED) transfer and the influence of planarity in the stilbazolium ring on the first hyperpolarizability are also discussed. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
210.
Refractive indices and their dispersion in the wavelength range from 365 nm to 2325 nm and transmission ranges of the tetragonal melilite‐type germanates Sr2MgGe2O7, Sr2ZnGe2O7 and Ba2ZnGe2O7 were determined. The uniaxial positive crystals Sr2MgGe2O7 and Ba2ZnGe2O7 both offer the possibility for phase matched second harmonic generation, a detailed analysis of phase matching conditions is given. The refractive indices of Sr2ZnGe2O7 show an isoindex (isotropic) point at 467 nm. The investigation was performed on Czochralski grown large single crystals. The crystal structure of all three germanates were determined by means of X ‐ray diffraction. The results corroborate unmodulated melilite‐type structures at room temperature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献