A novel approach for the preparation of organic-siloxane oligomers and the creation of hydrophobic surface

In this paper, poly(acrylate-g-siloxane) with novel comb-like structure was designed and prepared so as to create a strongly hydrophobic polymer surface. In order to achieve this goal, a series of organic-siloxane oligomers with different chain lengths and a double bond were firstly synthesized through the catalytic reforming and hydrosilylation reaction. Then, poly(acrylate-g-siloxane) was prepared by the copolymerization of the resulting oligomers with acrylate via emulsion polymerization. The as-synthesized oligomers were characterized by ¹H NMR and UV spectrometry, and the morphologies and surface chemical compositions of the dried membrane were investigated by FT-IR, XPS, as well as AFM. XPS analysis result shows that the chemical composition of the membrane's surface was rich in polysiloxane segments, which could be responsible for an increase of surface water repellency (the contact angle could reach 115° at a lower content of polysiloxane). A further investigation suggest that the side chain length of siloxane in the poly(acrylate-g-siloxane) was the dominant factor in influencing the hydrophobicity of the membrane’ surface. When the siloxane chain length reaches to eight, the membrane's surface could exhibit the strongest hydrophobicity.     

Synthesis,Spectral, Solvent Dependent Linear and Nonlinear Optical Characteristics of (E)-N-(3-(3-(4(dimethylamino)phenyl)acryloyl) phenyl)quinolone-2-carboxamide

This paper presents the synthesis of novel organic compound (E)-N-(3-(3-(4(dimethylamino)phenyl)acryloyl)phenyl)quinolone-2-carboxamide, also known as Quinolinecarboxamide Chalcone (QCC) using aldol condensation and carboxamide formation method. The organic sample QCC was examined by FT-IR, ¹H NMR, ¹³C NMR and mass spectroscopic techniques, respectively. Linear and third-order nonlinear optical (TNLO) properties of QCC dissolved in polar solvents such as DMSO, DMF and Ethanol have also been studied. The order of nonlinear refractive index and nonlinear absorption coefficient of QCC was measured to be 10^?11 m²/W and 10^?5 m/W. The nonlinear refractive index (n₂) of QCC was attributed to negative nonlinearity due to self-defocusing effect, and nonlinear absorption coefficient (β) indicates the behaviors of saturable absorption (SA) and reverse saturable absorption (RSA). The real and imaginary features of the TNLO susceptibility (χ⁽³⁾) of QCC in polar solvents were calculated to be the order of 10^─7 esu. The spectral characteristics of solvent on TNLO susceptibility of QCC were discussed. The results divulged that the synthesized organic compound is a novel nonlinear optical (NLO) material for applications in photonics and optoelectronics.

     

Tm3+/Yb3+共掺铋碲酸盐玻璃中的高效蓝色上转换荧光

制备了高折射率Tm³⁺/Yb³⁺共掺杂铋碲酸盐玻璃，利用棱镜耦合法测量出玻璃在632.8和1550nm波长处的折射率分别为2.0365和1.9795. 对玻璃的吸收、荧光和红外透过光谱展开了测试与分析，根据Judd-Ofelt理论对吸收光谱进行拟合，求得Tm³⁺的振子强度参数Ω_t(t=2，4，6)分别为3.90×10^-20, 2.03×10^-20和9.03×10^{-2 关键词： 3+}/Yb³⁺共掺')" href="#">Tm³⁺/Yb³⁺共掺 铋碲酸盐玻璃 光谱参数 上转换荧光     

Perylene-containing polysiloxane: An effective candidate for corrosion protection of iron surface

A new modified polysiloxane, perylene-containing polysiloxane (PCP), was successfully synthesized by amine-terminated polysiloxane (ATP) and 3,4,9,10-perylene tetracarboxylic dianhydride. The synthesized compound was characterized by Fourier transform infrared spectroscopy (FT-IR) and ¹H nuclear magnetic resonance (¹H NMR). The thermal analysis of the PCP indicates that the modified polysiloxane has outstanding thermal stability. The PCP also possesses good fluorescence property. Due to the appearance of lone-pair electrons and π bond in PCP, it could be self-assembled on iron surface and thus used in the corrosion protection area. The PCP films were characterized by EIS (electrochemical impedance spectroscopy) and SEM (scanning electron microscopy). These results indicate that the films modified by PCP could protect the iron from corrosion efficiently.     

OMNIDIRECTIONAL HIGH REFLECTOR FOR INFRARED WAVELENGTH

We have purposed the design of omnidirectional high reflectors with wide bandwidth (nearly 6300A⁰) for the infrared wavelength. Using translational matrix method for numerical calculation, it is found that a complete photonic band gap high reflector covering the wavelength region 11500A⁰ to 17800A⁰ is obtained for the quarter wave stack air / (n_L n_H)⁷ / air by using the tellurium (n=4.60) and TiO₂ (n=2.35) as material of high reflective index and SiO₂(n=1.45) low refractive index. Due to high refractive index of contrast of the structure i.e. SiO₂/tellurium, a large complete photonic band gap, omnidirectional high reflector, has been observed for the infrared wavelengths. This type of omnidirectional high reflector can be used in telecommunication. Besides this, we have studied the effective refractive indices (phase and group) of the proposed structures. It is observed that the effective refractive indices (phase and group) of the high omnidirectional reflector band are largely changed near the band edges due to the high refractive index of contrast, and the reflections from the internal interfaces of the structure.     

Large refractive index with vanishing absorption in optical fibers

We propose and demonstrate a novel scheme for realizing large refractive index with vanishing absorption in a three-level quantum system consisting of the energy levels of Er³⁺-doped ZrF₄–BaF₂–LaF₃–AlF₃–NaF (ZBLAN) optical fiber. It is found that the refractive index of the probe field can be controlled via the coherent coupling field and incoherent pumping field. The switching from negative refractive index to positive refractive index and manipulation of the value of the index of refraction while maintaining vanishing absorption of the probe field can be achieved via tuning the detuning of the coherent coupling field. Our scheme may provide some new possibility for technological applications in fiber communication.     

A test of virtual vacuum polarizations in a strong electromagnetic field

A strong electromagnetic field may modify the refractive index of the normal vacuum, which can be reduced to the light-light scattering amplitude via virtual vacuum polarizations in a microscopic sense. In order to observe the increase of the refractive index, Cherenkov light emissions associated with relativistic electrons into the strong field can be utilized as an experimental probe. In this letter, we will present the results of an experimental search for Cherenkov emission with a laser intensity of 10¹⁷ W/cm² with a wavelength of 800 nm and an electron beam of 35.4 MeV/c, in which the expected Compton energy and indications of unexpected lower energies in the visible range were observed.     

PVP掺杂-ZrO2溶胶-凝胶工艺制备多层激光高反射膜的研究

以丙醇锆(ZrPr)为锆源，二乙醇胺(DEA)为络合剂，原位引入聚乙烯吡咯烷酮(PVP)，在乙醇体系中成功地合成了PVP掺杂-ZrO₂溶胶.采用旋涂法在K9玻璃基片上制备了PVP-ZrO₂单层杂化薄膜.用不同掺杂量的PVP-ZrO₂高折射率膜层与相同的SiO₂低折射率膜层交替沉积四分之一波堆高反射膜.借助小角X射线散射研究胶体微结构，用红外光谱、原子力显微镜、紫外/可见/近红外透射光谱、椭圆偏振仪以及1064nm的强激光辐照实验对薄膜的结构、光学和抗激光损伤性能进行表征.研究发现，体系组成的适当配置可以在溶胶稳定的前提下实现ZrPr的充分水解，赋予薄膜良好的结构、光学和抗激光损伤性能.杂化体系中，DEA与ZPr之间强的配合作用大大降低了ZrO₂颗粒表面羟基的活性，使得PVP大分子只是以微弱的氢键与颗粒的表面羟基作用而均匀分散于ZrO₂颗粒的周围，对颗粒的形成和生长无显著影响.因而在实验研究范围内，随PVP含量的增大，PVP-ZrO₂杂化膜层的折射率和激光损伤阈值均无显著变化.但是，薄膜中均匀分布的PVP柔性链可以有效促进膜层应力松弛，显著削弱不同膜层之间的应力不匹配程度、大大方便多层光学薄膜的制备.当高折射率膜层中PVP的质量分数达到15%—20%时，膜层之间良好的应力匹配使得多层高反射膜的沉积周期数可达到10以上.沉积10个周期的多层反射膜，在中心波长1064nm处透射率约为1.6%—2.1%，接近全反射特征，其激光损伤阈值为16.4—18.2J/cm²(脉冲宽度为1ns). 关键词： 溶胶-凝胶 2')" href="#">PVP-ZrO₂ 高反射膜 激光损伤     

Fluorescent enhancement effect in heterometallic terbium-lanthanum hybrid molecular materials obtained by functional bridge grafting to silica network

A new monomer, TBBA-APMES, has been synthesized by grafting 3-aminopropyl-methyl-diethoxylsiliane (APMES) to 4-tert-butylbenzoic acid (TBBA) and characterized by H NMR, C NMR and Fourier transform infrared (FT-IR). The monomer acts as a functional ligand for Tb and La ion and as a sol-gel precursor. Luminescent hybrid materials consisting of terbium-lanthanum complex covalently bonded to a silica-based network have been obtained in situ via a sol-gel approach. Through the co-hydrolysis and polycondensation, Tb³⁺ and La³⁺ can be introduced in the same molecular hybrids through the chemical Si-O network and fluorescent enhancement is observed. The luminescent behavior has been studied with the different ratios of Tb³⁺-La³⁺, suggesting that the luminescence intensities of hybrids can be enhanced obviously by the existence of La³⁺. The enhanced fluorescence effect may be due to the strengthening of intramolecular energy transfer efficiency by La³⁺.     

PEG crosslinked poly(vinylbenzene boronic acid) polymer electrolytes for Li-ion batteries

Poly(4-vinylbenzeneboronic acid), PVBBA was synthesized via free-radical polymerization of 4-vinylbenzeneboronic acid (4-VBBA) and followed by crosslinking with polyethylene glycol (PEG) with different molecular weights to produce boron containing crosslinked polymers. Prior to crosslinking, the materials were doped with CF₃SO₃Li at several stoichiometric ratios to get PVBBAPEGX-Y where X is the molecular weight of PEG and Y is the EO/Li ratio. The materials were characterized by using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC). The ionic conductivity of these novel crosslinked electrolytes was studied by dielectric-impedance spectroscopy. Li-ion conductivity of these polymer electrolytes depends on the length of the side units as well as the doping ratio. PVBBAPEG200-10 illustrated a satisfactory ionic conductivity of 3.1 × 10^?5 S/cm at 20 °C and 1.8 × 10^?3 S/cm at 100 °C.     

番红花红T光敏感光致聚合物全息存储材料

制备了一种以番红花红T为光敏剂的新型全息存储材料,主要用Ar⁺激光器的514.5nm波长的绿光研究材料的全息特性.研究表明,该材料具有较高的衍射效率、曝光灵敏度和较大的折射率调制度,衍射效率近40%,灵敏度为7.22×10^-4cm²/mJ,折射率调制度为3.65×10^-4,同时,在读出时必须考虑布拉格偏移对全息存储的影响.在介质膜中存储了全息图像,再现图像较为清晰,说明该材料适合用作高密度全息存储介质. 关键词： 全息存储 光致聚合物 衍射效率 布拉格偏移     

Analysis of non-linear refractive index influences on four-wave mixing conversion efficiency in semiconductor optical amplifiers

In this paper, we have analyzed the influences of non-linear refractive index on the four-wave mixing (FWM) characteristics in semiconductor optical amplifiers (SOAs). It has been shown that the generated FWM signal characteristics can be modified due to the variation of non-linear refractive index of the SOA's medium. The wave propagation in the SOA has been modeled using the nonlinear propagation equation taking into account gain spectrum dynamics, gain saturation, which depends on carrier depletion, carrier heating, spectral hole-burning, group velocity dispersion, self-phase modulation and two photon absorption. Simulation of optical wave evolution in the SOA has been carried out using the finite-difference beam propagation method (FD-BPM) both in time and spectral domains. Our simulation results confirm that higher FWM conversion efficiency and lower time bandwidth product are achieved for higher absolute values of non-linear refractive index. Moreover, non-linear refractive index is more efficacious for high power propagated waves in SOAs. Finally, we have studied the modification of waveguide refractive index due to the propagation of optical pulses. We have also shown that when |n₂|=1 cm²/TW, refractive index variation is in the order of 10^?4 to 10^?7 for high and low power input pulses, respectively.     

Laser induced memory bits in photorefractive LiNbO3 and LiTaO3

We study experimentally the formation of refractive index voxels (volume elements) in photorefractive LiNbO₃ and LiTaO₃ crystals illuminated with high irradiance femtosecond laser pulses. We used 150 fs pulses at 800 nm wavelength (energy 6–50 nJ) tightly focused inside the crystals in a single shot regime. This resulted in a formation of a micrometer size region of elevated refractive index, which may be used as memory bits in information storage/retrieval application. The maximum refractive index change of 5×10⁻⁴ was recorded in undoped LiNbO₃ at an average light intensity of ∼TW/cm² that is close to the breakdown threshold. A simple setup for photorefractive recording and in situ monitoring of the refractive index changes has been proposed. M. Sūdžius leaves from: the Institute of Materials Science and Applied Research of Vilnius University, Lithuania.     

Dosimetry techniques

The formation and annealing of defects in ion implanted silicon dioxide layers and in connection with them the refractive index change are of high interest for the production of electronic and integrated optical devices.

Several studies have shown that the ion implantation in fused silica leads to a compaction of the material and in consequence to an increasing of the refractive index.^1–6 On the other hand the defect formation in crystalline quartz is connected with a decreasing of the refractive index up to nearly the same value for ion implanted quartz and fused silica layers in the high dose region.^1,5 On the base of this effects optical waveguides had been produced by ion implantation in both material.^2,7–12 However, the nature of the mechanisms responsible for the defect formation and for the changes of the optical properties are not well understood.

This paper reports on the ion dose and annealing temperature dependence of several defects in connection with the refractive index change.     

湍流气象探空仪的研制及其性能分析

 最新研制的湍流气象探空仪是将温度脉动仪附加在常规气象探空仪上,实现了两路折射率结构常数、温湿压常规气象参数、温度谱等测量。通过在合肥和长春的实验表明该系统具有较高的测量精度和稳定性,在高空低温动态条件下探空仪系统噪声与温度脉动仪地面常温静态条件下的噪声相当。探空系统噪声引起的等效折射率结构常数小于2×10^-18 m^-2/3。能服务于激光传输、大气质量评价及天文台选址等相关领域对大气光学湍流研究的需要。     

Optical properties of selenium sulfide thin film produced via chemical dropping method

This paper describes the production of selenium sulfide (SeS₂) crystalline thin film on commercial glass substrates, via chemical bath deposition. Transmittance, absorption, dielectric constant and refractive index of the produced films were investigated by UV/VIS Spectrum. It was found that changes occurred on the characteristics of the films and they were determined as a function of selenium sulfide concentration, which varied between 2?×?10^?3 and 5?×?10^?3 M. The structure of the film was analyzed using FTIR spectrum. The calculated refractive index values fell between 1.5 and 1.6, whereas the transmission ratio of the films was around 80–90%. Moreover, a peak in the reflectance was observed at 320–330 nm for all investigated samples. The highest dielectric constant for the films was obtained at the deposition concentration of 0.005 M. This study is believed to be useful for thin film production.     

Laser beam deflectometry and C60 polymerized nanorods dynamics by surface interdiffusion

Laser beam deflectometry was used to follow the growth dynamic of C₆₀ nanorods via an interfacial diffusion and self-assembly phenomenon. The deduced average value of the interfacial diffusion coefficient D_int from the refractive index gradient was found to be of the order of 3.32 10^? 6 m²/s.     

Effects of refractive index modifiers and UV light on an epoxy-functional inorganic-organic hybrid sol-gel derived thin film system

Thin film systems consisting of (3-glycidyloxypropyl)trimethoxysilane (GDPTMS), dimethyldimethoxysilane (DMDMOS) and, either zirconium(IV) n-propoxide (Zr(OPrⁿ)₄) or diphenyldimethoxysilane (DPDMS) were synthesised via the sol-gel method. GDPTMS and DMDMOS were employed as the main network formers, whereas Zr(OPrⁿ)₄ or DPDMS was both a network former and a refractive index modifier. The comparative effects of Zr and DPDMS content, and UV light on the optical and thermal properties of the system were evaluated. Refractive index measurements and cross-sectional scanning electron microscopy of the resultant thin films were performed. The thermal stability of each system, in terms of temperature at 10% mass loss, was characterised by dynamic thermogravimetry. It was demonstrated that the selection of refractive index modifier along with UV irradiation plays an important role in tuning the optical and thermal properties of an epoxy-functional inorganic-organic hybrid sol-gel derived thin film system.     

Chemical relaxation of cis-1,4-polybutadiene radiation-crosslinked at high pressure

Chemical relaxation for cis-l,4-polybutadiene crosslinked at 7000 kg/cm² by γ-irradiation was compared with that for one crosslinked at atmospheric pressure. The degree of thermal degradation was similar in both specimens, but the specimen crosslinked at 7000 kg/cm² formed fewer new networks in the initial stage than the specimen crosslinked at atmospheric pressure. The G value for the formation of crosslinking points was proportional to the-0.5 power of the dose rate at high pressure. This indicates that the radiation-induced crosslinking at high pressure proceeds in a chain reaction as proposed from the high G value in a preceding paper. The lower formation of new network chains for the specimens crosslinked at 7000 kg/cm² is concluded to be due to lower mobility of polymer radicals that crosslink by recombination near the clusters of crosslinking points produced by the chain reaction.