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1.
用波导产生倍频波时,如果倍频波进入辐射模区,仍然有相匹配问题。契伦可夫辐射式倍频不是自动地实现相匹配的。相匹配要求导波基波模式场,倍频传输场(自由波),倍频触发场,以及经多次反射透射后的辐射场的迭加形成的总辐射场处于同步的相匹配状态。根据这个相匹配的分析,提出波导契伦可夫相匹配的特有的方法,那就是对波导的模色散进行设计,并指出非对称波导的特有优点,是改变一个边界上的反射相变,即选择不同色散的线性材料作包层,由此可得到相匹配的高效契伦可夫倍频辐射。 相似文献
2.
FANG Qi LEI Hong CUI Yuezhi HUANG Zhenli XUE Gang & YU Wentao . State Key Laboratory of Crystal Materials Shandong University Jinan China . School of Information Science Engineering Shandong University Jinan China . Department of Chemical Engineering Light Industry College of Shandong Jinan China . Key Laboratory of Biomedical Photonics Ministry of Education Huazhong University of Science Technology Wuhan China 《中国科学B辑(英文版)》2005,48(3)
Organic nonlinear optics (NLO) is also called mo-lecular nonlinear optics. In recent years organic mate-rials have been intensively studied because of their large NLO coefficients and structural diversities[1―3]. Second harmonic generation (SHG) is a bas… 相似文献
3.
1INTRODUCTIONRecentlyorganicnonlinearoptical(NLO)materialsarebeingdevelopedforfre-quencyconversionoflaserinopto-electrics-Especiallybluelightisrequiredforopti-calmemoryofhighdensityrecording.Becauseadiodelaserisusedasalightsource,thenonlinearmaterialswhichhaveextremelyhighvalueofNLOcoefficientsandthetransmissionofblueregionarenecessary.Sincethesecond-orderNLOpropertyoforganiccompoundisderivedfromconjugateddelocalizedrrelectrons,thecompoundswhichhavebeenreportedhavefocusedonthenitroanil… 相似文献
4.
Crosslinking is one of the effective routes for improving the orientation stability of poledpolymer films. The derivative of polyvinyl alcohol containing 4-nitro-4'-alkoxystilbene andphoto-crosslinkable cinnamyl groups as side chains has been synthesized. The in-situ simul-taneous photo-crosslinking poling of synthesized polymer films has been performed. Thesecond order nonlinear optical coefficient d_(33) of poled film is 11 pm/V. The SHG mea-surements show that the break-over temperature of SHG signal is raised obviously afterirradiation, its orientation stability is doubled as compared with that of non-crosslinkingsamples. 相似文献
5.
William K. Bell Brandon M. Rawlings Brian K. Long R. Chad Webb B. Keith Keitz Lukas Häußling C. Grant Willson 《Journal of polymer science. Part A, Polymer chemistry》2014,52(19):2769-2775
A series of photocrosslinkable polymers bearing hyperpolarizable side chain chromophores was synthesized, poled and evaluated on the basis of the thermal stability of Second Harmonic Generation (SHG). Photoinitiation allowed for control of the onset of curing. Crosslinking was monitored by infrared spectroscopy and optimal conversion was achieved by applying a slow temperature ramp during exposure. The ultimate stability of the poled polymers was directly related to the number of crosslinking substituents that were attached to the chromophore pendant group. With two reactive groups per chromophore significant SHG was retained at temperatures above the initial polymer glass transition temperature. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2769–2775 相似文献
6.
Anupam Bhim Prof. Jean-Pascal Sutter Prof. Jagannatha Gopalakrishnan Prof. Srinivasan Natarajan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(6):1995-2008
The stuffed tridymite structure Ba(Zn/Co)1−xSi1−xM2xO4 (M=Al3+ and Fe3+) is explored for the possible multiferroic behavior and to develop new inorganic colored materials. The compounds were synthesized by employing conventional solid-state chemistry methods in the temperature range 1100–1175 °C for 24 h. The powder X-ray diffraction (PXRD) and Rietveld refinement studies indicate that the compounds stabilize in the P63 space group (no. 173). The refinement results were also rationalized by employing Raman spectroscopic studies. The compounds were found to be second harmonic generation (SHG) active and show weak ferroelectric behavior. The co-substitution of Co2+ and Fe3+ in the structure gives rise to a weak ferromagnetic behavior to the compound, BaCo0.75Si0.75Fe0.5O4, making it a multiferroic material. The optical studies on the prepared compounds exhibited blue color (Co2+ in Td geometry), purple color (Ni2+ in Td geometry), and simultaneous substitution of Co2+ and Fe3+ gives rise to blue-green color owing to metal-to-metal charge transfer (MMCT) effect. 相似文献
7.
P. R. Srikanth Sharma Peiguang Zhou Harry L. Frisch 《Journal of polymer science. Part A, Polymer chemistry》1996,34(6):1049-1058
We report the synthesis and characterization of interpenetrating polymer networks (IPNs) exhibiting nonlinear optical (NLO) properties. The network consists of aliphatic polycarbonate urethane (PCU) and poly(methyl methacrylate-co-N,N-disubstituted urea), with a nonlinear optical (NLO) chromophore incorporated into N,N-disubstituted urea. The full IPNs have only one Tg, as determined by differential scanning calorimetry (DSC), together with scanning electron microscopy (SEM) observations, suggest a single phase morphology. The thin films of IPNs are transparent and the unpoled samples produced second harmonic generation (SHG) signals at room temperature. This result indicates that the NLO chromophore is oriented noncentrosymmetrically during the IPN formation process and is tightly held between the permanent entanglements of the two component networks of the IPN. © 1996 John Wiley & Sons, Inc. 相似文献
8.
D. Antonucci D. de Ceglia A. D’Orazio M. De Sario V. Marrocco V. Petruzzelli F. Prudenzano 《Optical and Quantum Electronics》2007,39(4-6):353-360
In this paper we discuss the conditions to obtain the enhancement of second harmonic generation in a two-dimensional circular
photonic crystal AlGaAs cavity. The photonic crystal circular cavity offers the possibility of having high-Q resonance modes
with respect to those obtained with other types of photonic crystal lattices. The crystallographic cut of the AlGaAs provides
a strong nonlinear coupling between a transverse-magnetic (TM) polarized resonant mode at the fundamental wavelength and a
transverse-electric (TE) polarized resonant mode at second harmonic wavelength. The double resonance condition leads to a
strong improvement of the second harmonic generation process. A preliminary linear analysis has been performed by using the
finite-difference time-domain method, which includes the dispersive response of the material, modeled using the well-known
one-pole pair Lorentzian function. 相似文献
9.
SUN ChuanFu YANG BingPing & MAO JiangGao State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou China 《中国科学B辑(英文版)》2011,(6)
Metal iodates with a lone-pair containing I(V) that is in an asymmetric coordination geometry can form a diversity of unusual structures and many of them are promising new second homonic generation (SHG) materials. They exhibit wide transparency wavelength regions, large SHG coefficients and high optical-damage thresholds as well as moderately high thermal stability. In this paper, the structures and properties of the metal iodates are reviewed. The combination of d0 transition-metal cations with the iodate... 相似文献
10.
本文描述我们设计的带抗共振环 (ARR)的对撞脉冲锁模 (CPM )非稳腔Nd :YAP和Nd :YAG激光器 ,该激光腔结合了CPM腔脉宽窄、工作稳定和非稳腔输出能量高的特点 ,是一理想的高功率激光器 同时选择了KTP、BBO和LBO等优良非线性晶体作为腔内倍频元件 ,实现高效倍频转换 获得× 1 0mJ和 5GW /cm2 的高能量和高功率绿光皮秒脉冲输出 ,倍频转换效率高达 ( 50~ 70 ) % 相似文献