Defect Complexes and Optical Properties of Doubly Doped Lithium Niobate Crystals

The effect of defect complexes related to the presence of protons on the optical properties of LiNbO₃:Y(0.24):Mg(0.63) and LiNbO₃:Gd(0.25):Mg(0.75) (wt %) crystals has been studied using IR absorption spectroscopy, photoinduced light scattering, and laser conoscopy. The results indicate that the absorption bands at frequencies of 3483 and 3486 cm^–1 correspond to vibrations of a V _Li ^- –OH^? defect complex. To a Mg _Li ⁺ - Mg _Nb ^3- –OH^?defect complex in the LiNbO₃:Gd(0.25):Mg(0.75) crystal correspond bands at frequencies of 3526 and 3535 cm^–1. In the LiNbO₃:Y(0.24):Mg(0.63) crystal, we have detected an anomalous opening of the speckle structure of the photoinduced light scattering indicatrix.     

铌酸钾锂晶体的生长与性能

使用坩埚下降法成功生长了尺寸为φ10mm50mm、四方钨青铜结构、透明铌酸钾锂晶体,讨论了引起晶体开裂的主要原因,研究了该晶体的光透过性能和介电性能,室温下该晶体的介电常数ε33=127,ε11=376,居里温度为380°     

铌酸钾锂晶体的生长技术

铌酸钾锂被认为是目前综合性能指数最高的非线性光学晶体,在半导体二极管蓝激光倍频方面有广阔的应用前景。本文综述了用于蓝光倍频的铌酸钾锂晶体生长研究进展,比较了不同生长方法的优缺点,报道了我们在该晶体坩埚下降法生长研究方面的最新成果。     

Structural Defects and Photoluminescence in Zinc-Doped Lithium Niobate Crystals

Inorganic Materials - We demonstrate that increasing the zinc concentration in Zn-doped lithium niobate crystals to their first concentration threshold (~3.0 mol % ZnO) leads to a decrease in...     

Photoelectric Fields and Band Gap in Doped Lithium Niobate Crystals

Photoinduced light scattering and optical spectroscopy have been used to study the photorefractive effect and determine the band gap in nominally undoped congruent and stoichiometric lithium niobate crystals, as well as in a series of congruent LiNbO₃ crystals doped with Mg, Zn, B, Gd, Y, and Er cations and LiNbO₃ single crystals codoped with Mg:Gd, Mg:Fe, Mg:Y, and Mg:Ta.     

LiNbO3声表面波特性及其应用

LiNbO3因其优异的压电性能和声表面波特性被广泛应用于声表面波器件中.着重介绍LiNbO3的压电性能、声表面性能及其薄膜制备技术,对通过不同制备工艺生长出的LiNbO3薄膜的质量和声表面波性能进行了比较,并简要介绍了LiNbO3在声表面波领域应用的新进展.     

Preparation and Characterization of Lithium Niobate Single Crystals Activated with Magnesium and Boron

Inorganic Materials - A technologically feasible process has been proposed for the preparation of homogeneous single-phase magnesium–boron codoped lithium niobate growth charge. It has been...     

Preparation and Characterization of Lithium Niobate Single Crystals Doped with Zinc and Erbium

Inorganic Materials - This paper reports a process for the growth of zinc–erbium codoped lithium niobate single crystals using a growth charge synthesized from a Nb2O5:Zn:Er precursor and...     

Improved Long-Term DC Drift in OH-Reduced Lithium Niobate Optical Intensity Modulators

Long-term dc drift of lithium niobate optical intensity modulators is successfully reduced by exclusion of OH(-)ions from the lithium niobate substrate. In this regard, the titanium-indiffused waveguide is prepared on a commercial OH-free substrate under a dry gas atmosphere.The dc drift measured for these hermetically sealed modulators indicates a possibility for continuous operation over 20 years at 50°C.     

Optical Properties of Ladder Type Single Crystals

The optical properties of (M ₂ Cu ₂ O ₃ ) _m (CuO ₂ ) _n (M=Ca, Sr, Y, Bi) crystals containing the ladder-type plane Cu ₂ O ₃ were investigated by spectroscopic ellipsometry method in the range 0.5-5.0 eV. The experimental data were analyzed in order to reveal the difference in the microstructure between superconducting (SC) and non-superconducting (NSC) single crystals. The contributions to the optical response due to the electronic excitations of free and bound carriers were analyzed.     

Broadly Tunable, Mode-Hop-Tuned cw Optical Parametric Oscillator Based on Periodically Poled Lithium Niobate

We describe a broadly tunable, cw optical parametric oscillator (OPO) based on periodically poled lithium niobate. The OPO can be tuned over a broad region in the mid IR (2900-3100 cm(-1)) covering the important C-H stretch region while a high spectral resolution (<0.1 cm(-1)) is maintained. The OPO is the light source for a field-portable photoacoustic spectrometer for gas-phase monitoring of volatile organic compounds.     

An Optical Thermometer Exploiting Periodically Poled Lithium Niobate for Monitoring the Pantographs of High-Speed Trains

Optical thermometers have been widely investigated. Here, the temperature behavior of second harmonic generation (SHG) in periodically poled lithium niobate (PPLN) substrates is analyzed; indeed, the QPM tuning in PPLN devices and the obtained SHG efficiency depend on the crystal thermal expansion and dispersion, particularly in the case of guided propagation. Therefore, such devices are suitable to realize optical thermometers for demanding applications. This investigation originated with the request of a thermometer to be installed on the pantographs of high-speed trains. Therefore, it must be sturdy and reliable, but it has even to work in an EMD environment. The temperature behavior of the SHG was theoretically modeled and experimentally validated at 1550 nm, in both bulk propagation and APE channel waveguides. In the first case, by using a 10-mW source, which was obtained from a laser diode and a fiber amplifier, an accuracy of 0.3 degC was found. The pump power was about three orders of magnitude smaller in guided propagation. In view of testing on the trains, our investigation resulted in the design of a device without mechanical contacts with the input and output fibers. Since it works in free propagation, there are no serious alignment and packaging problems. The performances, which are expected to be the same of our tests, widely satisfy all the requirements for working effectively in a strongly hostile and EMD environment and for giving accurate measurements on a wide range of temperatures     

近化学计量比铌酸锂晶体的研究进展

介绍了近化学计量比铌酸锂晶体的主要生长方法及其特点,总结了近化学计量比铌酸锂晶体的主要性能,通过与同成分铌酸锂晶体的比较,指出了近化学计量比铌酸锂晶体的主要应用优势,明确了该类晶体今后的研究重点.     

铌酸钾锂晶体的生长研究

首次使用坩埚下降法生长了蓝光掊频晶体铌酸钾锂K₃Li_2-xNb_5＋xO_15＋2_x（0＜x＜0．5）,探讨了该晶体的最佳生长条件,包括组份选择、原料处理、炉温控制、温场设计等,成功地生长出直径10mm、长度25mm的透明KLN晶体．     

Photorefractive Correction of the Coupling Ratio of an Integrated Optical Directional X-Coupler on a Lithium Niobate Substrate

Technical Physics Letters - The possibility of correcting the power coupling ratio of an integrated optical directional X-coupler upon excitation of a local photorefractive response in the...     

Optical Properties of New Type of Superconductor-Semiconductor Metamaterial Photonic Crystals

Based on the fundamentals of the characteristic matrix method, we theoretically investigate the optical properties of onedimensional superconductor metamaterial photonic crystals. The photonic crystals are composed of a superconductor layer and two semiconductor metamaterial layers of In_0.53Ga_0.47As with different doping densities. The numerical results show negative values in permittivity of the metamaterial layer along a broad band of the incident radiation. The negative values show a significant effect on the optical properties of the present structure. Moreover, the optical properties of our design can be controlled by different parameters such as thicknesses of the layers, the operating temperature and the doping density. Our results may be suitable for different applications in the optical community.