共查询到20条相似文献,搜索用时 15 毫秒
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在LiNbO3中掺进0.015mass%MnCO3和 0.1mass%CeO2,以Czchralski法生长Li/Nb比为1.38的近化学计量比Ce∶Mn∶LiNbO3(Ce∶Mn∶SLN)晶体和Li/Nb比为0.946的同成分Ce∶Mn∶LiNbO3(Ce∶Mn∶CLN)晶体.测试了晶体的红外光谱和紫外可见吸收光谱,讨论了Ce∶Mn∶SLN晶体OH-吸收峰和吸收边移动机理.利用二波耦合光路测试了晶体的指数增益系数,Ce∶Mn∶SLN晶体指数增益系数Γ达到27 cm2-.同时,研究了Ce∶Mn∶SLN指数增益系数提高的机理. 相似文献
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The time dependence of the photorefractive light scattering in lithium niobate single crystals of the congruent composition (LiNbO3) doped by “photorefractive” Cu cations (0.015 wt %) is studied for a radiation power of 160 mW. The data for the photorefractive scattering are confirmed by changes in Raman scattering spectra. 相似文献
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Prescription for optimizing holograms in LiNbO(3):Fe:Mn 总被引:4,自引:0,他引:4
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LiNbO3:Ru晶体的光折变特性研究 总被引:1,自引:1,他引:1
采用丘克拉斯基法生长了单掺杂的LiNbO3∶Ru晶体,并对其作氧化处理。实验研究了LiNbO3∶Ru晶体二波混频条件下光栅记录特性和波长的依赖关系;并且研究了氧化处理对其透射谱和光栅记录特性的影响。研究结果表明,LiNbO3∶Ru晶体的最佳记录波长为458 nm;氧化处理会增加LiNbO3∶Ru晶体对光的吸收,同时提高光栅记录的灵敏度和饱和衍射效率,表现了不同于LiNbO3∶Fe晶体的氧化态依赖特性。分析认为,LiNbO3∶Ru晶体的反常氧化态依赖特性可能是由于出现了电子通道效应的暗衰减机制,以及Ru存在多个价态所造成的。 相似文献
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Holograms may be recorded in photorefractive LiNbO3:Cu with pulsed infrared light (wavelength =1064 nm, Q-switched Nd:YAG laser), if the crystals are previously or simultaneously illuminated with a green (=532 nm) light pulse. We study refractive index changes and time constants of as-grown and thermally treated crystals with different copper concentrations. A model explaining this effect is discussed. 相似文献
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掺Ce,Fe系列LiNbO3晶体光折变效应光存储特性 总被引:5,自引:4,他引:5
研究了系列Ce:Fe掺杂以及不同后处理态(生长态、还原态和氧化态)铌酸锂晶体的透过率光谱和光折变全息存储特性。实验结果表明单掺Ce铌酸锂晶体具有较好的图像存储质量和较宽的透过率光谱范围,二波耦合增益相对较低;高掺杂铌酸锂样品的透过率光谱范围较窄,光折变二波耦合增益较低。晶体的后处理对铌酸锂样品的光折变特性影响明显,双掺Ce:Fe还原态铌酸锂晶体具有较高的二波耦合增益;氧化态样品具有较大的透过率光谱范围;还原态样品具有较大的光折变二波耦合增益特性。实验结果还表明在同种样品中难于同时获得大的二波耦合增益和图像存储质量。 相似文献
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We have observed quasinondestructive holographic storage with a continuous-wave laser at lambda = 532 nm in near-stoichiometric LiNbO3 doped with Tb and Fe. This crystal showed an exceptionally long grating decay time and also exhibited a fast color change upon exposure to ultraviolet (UV) light. It was demonstrated that the grating recorded from the UV-exposed, colored state can be continuously read out over 9 h at a reading intensity as high as 8 mW/cm(2). In addition, the written grating could be easily erased with UV illumination which returned the crystal back to the original colored state. 相似文献
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We propose a new way to record images in a photorefractive LiNbO3 crystal. This method involves only a single object light without any reference light. We believe that the recording is attained by fanning holograms that result from interference between the object light and its scattered light. Although volume gratings are involved, the recorded pattern can be viewed not only with a laser light beam that is incident over a certain angular range but also with white light. 相似文献
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Multiplexing holograms in LiNbO3:Fe:Mn crystals 总被引:7,自引:0,他引:7
Persistent holograms are recorded with red light in lithium niobate crystals doped with manganese and iron. Different erasure mechanisms are investigated, and a recording schedule for multiplexing holograms with equal diffraction efficiencies is proposed. To test the recording schedule experimentally, we multiplex 50 plane-wave holograms with the proposed recording schedule. 相似文献
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Mambetova K. M. Shandarov S. M. Orlikov L. N. Arestov S. I. Smirnov S. V. Serebrennikov L. Ya. Krakovskii V. A. 《Optics and Spectroscopy》2019,126(6):781-786
Optics and Spectroscopy - We present results of experimental studies, theoretical analysis, and numerical modeling of specific features of photorefractive gratings that are formed by a... 相似文献
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The LiNbO3 crystal co-doped with ZrO4 and Fe2O3 has been grown with [Li]/[Nb]=0.85 and 1.20, respectively, by the Czochralski method in air atmosphere. The incident exposure energy flux threshold for the light-induced scattering was characterized to investigate the scattering properties of the crystals. Applying the results of the incident exposure energy flux threshold effect, the photorefractive properties at different laser wavelengths (473 nm and 532 nm) were also measured by using the typical two-wave coupling experiments. The results show that Zr:Fe:LiNbO3 crystal has a larger refractive index change, higher recording sensitivity and larger two-wave coupling gain coefficient at 473 nm wavelength than those obtained at 532 nm wavelength under the same experimental conditions. Moreover, the photorefractive properties decrease with the increasing [Li]/[Nb] ratios. The material of Zr:Fe:LiNbO3 crystal is a promising candidate for blue photorefractive holographic recording. 相似文献
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Hong-Shyuan Chen Tzu-Wei Lin Jung-Ping Liu Yueh Ouyang Hsiu-Fong Chang 《Optical Review》2009,16(3):332-334
Holographic recordings in a LiNbO3 crystal using ordinary and extraordinary light in transmission-type geometry were performed. The system parameters of storage
capacity (M/#), sensitivity, and signal-to-noise ratio were measured. Although extraordinary light will induce stronger fanning light
(nonlinear enhanced scattered light) in LiNbO3, our experimental results indicate that the system using extraordinary light is superior to that using ordinary light. Our
demonstrations and results can help to optimize the holographic recording in some applications of volume holographic optical
element (VHOE), such as wavelength division multiplexing (WDM) filters in optical communication. 相似文献
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T. Volk B. Maximov T. Chernaya N. Rubinina M. Wöhlecke V. Simonov 《Applied physics. B, Lasers and optics》2001,72(6):647-652
LiNbO3:Zn single crystals and powders were studied by precise X-ray diffraction methods. Structural refinement yielded new models
of the intrinsic defect structure valid for different Zn concentration ranges. For concentrations up to 7 at. % in the crystal,
Zn ions incorporate onto Li sites; at higher concentrations Zn ions are found on both Li and Nb sites. Photorefractive properties
of LiNbO3:Zn are discussed in the context of the deduced defect models. A smooth increase in the photoconductivity up to 7 at. % Zn
is accounted for by a decrease of Nb antisites. Steeper growth of the photoconductivity at higher Zn concentrations is related
to vanishing Li vacancies.
Received: 17 November 2000 / Revised version: 23 January 2001 / Published online: 20 April 2001 相似文献
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O. Momtahan G.H. Cadena A. Makhmalbaf A. Adibi 《Applied physics. B, Lasers and optics》2008,90(3-4):519-525
In this paper, we report the observation of electron tunneling during two-center recording in LiNbO3:Fe:Mn doped with high Fe concentration. Unlike tunneling in the singly doped lithium niobate that erases the hologram, the
effect in two-center recording can improve the diffraction efficiency of the hologram after the recording while it is kept
in the dark. A detailed study of this effect in LiNbO3:Fe:Mn is presented both theoretically and experimentally. We show that the hologram strength may increase or decrease due
to tunneling, depending on the experimental condition of recording.
PACS 42.40.-i; 42.70.Ln; 42.40.Lx 相似文献
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在LiNbO3中掺进CeO2和Co3O4,以Czchralski技术首次生长Ce:Co:LiNO3, Ce:LiNbO3, Co:LiNbO3晶体.通过测试Ce:LiNbO3, Co:LiNbO3和Ce:Co:LiNbO3晶体的指数增益系数, 位相共轭反射率和响应时间,计算晶体的有效载流子浓度和光电导.Ce离子能提高LiNbO3晶体光折变灵敏度,Co离子能提高LiNbO3晶体的响应速度和抗光致散射能力,从而Ce:Co:LiNbO3晶体具有较高的指数增益系数,位相共轭反射率,响应速度.Ce:Co:LiNbO3晶体具有优良的光折变性能. 相似文献
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We report on the fabrication and properties of He-implanted waveguides in lithium niobate, which are additionally doped with
copper by using an ion-exchange process. We show that the photorefractive sensitivity in the waveguides is increased by a
factor of 3000.
Received: 23 November 1998 / Revised version: 15 February 1999 / Published online: 12 April 1999 相似文献
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The role of carrier mobility in holographic recording in LiNbO3 总被引:1,自引:0,他引:1
We investigate the role of carrier mobility in holographic recording in LiNbO3 crystals. Both normal holographic recording (single wavelength, single trap) and two-center recording are considered, and
the differences between the performances of the two methods are explained. We show that increasing mobility by using stoichiometric
crystals or by doping with Mg does not improve sensitivity considerably, but does reduce M/# by at least one order of magnitude.
Received: 22 February 2001 / Revised version: 5 March 2001 / Published online: 27 April 2001 相似文献