高掺镁富锂铌酸锂晶体的倍频及抗光折变性能

测量了新的一系列铌酸锂晶体—高掺镁富锂铌酸锂晶体的倍频和抗光折变性能,研究了其抗光折变的机制.结果表明:该系列晶体较同成分晶体和只掺镁晶体具有更优异的倍频和抗光折变性能,其抗光折变能力增强的宏观机制也是光电导增大.

一种高效率的光折变晶体——掺杂铌酸锂

本文介绍了一种特殊掺杂的铌酸锂单晶在光折变效应方面的若干实验研究结果。这些结果表明:这种具有易于获得大尺寸单晶等特点的材料是一种高效率的光折变晶体。

BSO晶体中光折变增益与入射面情况的依赖关系

用两波混频方法在514.5nm(氩离子激光器)对BSO晶体中光折变增益与入射面情况的依赖关系进行了研究,由于BSO晶体围绕<110>轴旋转时受主能级状态的影响,从而光折变增益将取决于衍射效率的改变。

光折变晶体中光互联的研究

光折变晶体中光互联的研究高宏，张家森，窦硕星，朱镛，张时明，叶佩弦（中国科学院物理所北京１０００８０）光折变材料由于有大的电光系数，在这些材料中光束耦合的效率非常高，因此在相当弱的光强下也能发生有效的相互作用，从而可以制成一些新颖的光子学器件。本文对...

铜版纸水性上光工艺对上光质量的影响

为了研究铜版纸水性上光涂布工艺对印品质量的影响,得到最佳的涂布工艺参数,使用IGT印刷适性仪在一定印刷条件下对铜版纸实地打样,分别在不同的涂布速度与涂布厚度下,对各印刷样张进行水性光油上光涂布,通过测试各样张的光泽度和耐折度,比较不同工艺条件下上光前后印品光泽度和耐折度的变化,探讨涂布速度、涂布厚度对水性上光质量的影响。结果表明,涂布速度和涂布厚度与印品的光泽度和耐折度有关。上光印品的光泽度和耐折度会随着涂布速度和涂布厚度的增大而增大,其增量有最大值。合理匹配上光工艺的这两个条件,能够获得最佳上光工艺参数。

Study on the Refractive-Index Structure Coefficient C_N^2

Based on the regularities of temperature fluctuation,the atmo- sphere below an altitude of 71km above ground is divided into 6 sublayers. For each of them the calculation formulae of temperature and pressure are derived.The calculated results at any altitude in the range under considera- tion agree well with the values laid down in the table of“U.S.Standard At- mosphere”.From this the formula for the refractive-index structure coeffi- cient C_N^2,of much importance in the research of adaptive optics,is obtained for the corresponding altitudes.

Influence of stress birefringence on the performance of a FBG pressure sensor

The effects of using overall affix and two-spot affix between the FBG and underlay on the characteristics of the pressure sensors are compared both experimentally and theoretically.It is found that overall affix can produce large nonlinear effect on the characteristics of output of the sensors.The nonlinear effect caused by the expanded spectral width mainly due to the stress birefringence and the stress grads etc.The experimental result shows that the spectral width caused by using overall affix is 0.28 nm and the linearity can have up to 1.89% of increasing by using two-spot affix.The method of two-spot affix can improve response characteristics of the sensor which is benefit to achieve wavelength demodulation and to improve measurement precision.

A Method for the Removal of Ray Refraction Effects in Multibeam Echo Sounder Systems

To a multibeam echo sounder system (MBES), under water sound refraction plays an important role in depth measure- ment accuracy, and errors in sound velocity profile lead to inaccuracies in the measured depth (especially for outer beams). A method is developed to estimate the sound velocity profile based on the depth measured by vertical beam. Using this depth and other pa- rameters, such as t (sound pulse propagation time), θ (beam inclination angle), etc. We can estimate a simple sound velocity profile with which the depth error has been reduced. This method has been tested with a real dataset acquired in the East China Sea.

Optical Trap 2D Array by Acoustic Modulation

In this artilce a new optical trap 2D array by the acoustic modulation is proposed. Based on the ＂called＂ acoustic-elasticity of the fluid embedding trapped microparticle, the expression describing the refractive index induced by cross-interference of two perpendicular ultrasonic waves is approximately derived. By simulation, the 2D array of the Graded-refractive index lenses appeared in the fluid layer with certain strain-acoustic constant and thickness. The trapping capability of the plane-wave laser beam propagating through those lenses is shown out, and the appearance of the optical trap 2D array has been affirmed.

Interferometer Based on a D-shape Chaotic Optical Fiber for Measurement of Multiparameters

An interferometer based on a D-shape chaotic optical tiber tor measurement ot multiparameters was proposed. The sensing structure relied on a D-shape fiber section spliced in between two singlemode fibers and interrogated in transmission. The optical spectrum was composed by multiple interference loss peaks, which were sensitive to the refractive index, temperature and strain-maximum sensitivities of 95.2 nm/RIU, 10.5 pm/℃ and -3.51 pm/με, respectively, could be achieved.

Effects of temperature on the dynamic evolution of two-photon photorefractive screening spatial solitons

We investigate theoretically the temperature effects on the evolutions of both bright and dark screening spatial solitons in biased two-photon photorefractive crystals.For a stable bright or dark two-photon screening spatial soliton originally formed in a crystal at a given temperature,when the crystal temperature changes,it will evolve into another stable screening soliton if the temperature change is quite small,while it will become unstable or break down if the temperature change is large enough.The spatial shape of a stable two-photon screening spatial soliton can be changed by appropriately adjusting the crystal temperature.

A highly sensitive “turn-on” fluorescent probe for bovine serum albumin protein detection and quantification based on AIE-active distyrylanthracene derivative

A sulfonated 9,10-distyrylanthracene derivative with aggregation-induced emission (AIE) property is designed and synthesized. It shows a highly sensitive and selective fluorescence enhancement property for bovine serum albumin (BSA) protein detection and quantification. Analysis on the interaction between the probe molecule and BSA reveals the essential role of the hydrophobic cavities of the protein folding structure.

Linear and Nonlinear Optical Properties of Spherical Quantum Dots:Effects of Hydrogenic Impurity and Conduction Band Non-Parabolicity

Simultaneous effects of an on-center hydrogenic impurity and band edge non-parabolicity on intersubband optical absorption coefficients and refractive index changes of a typical GaAs/AlxGa1-xAs spherical quantum dot are theoretically investigated, using the Luttinger-Kohn effective mass equation. So, electronic structure and optical properties of the system are studied by means of the matrix diagonalization technique and compact density matrix approach, respectively. Finally, effects of an impurity, band edge non-parabolicity, incident light intensity and the dot size on the linear, the third-order nonlinear and the total optical absorption coemcients and refractive index changes are investigated. Our results indicate that, the magnitudes of these optical quantities increase and their peaks shift to higher energies as the influences of the impurity and the band edge non-parabolicity are considered. Moreover, incident light intensity and the dot size have considerable effects on the optical absorption coefficients and refractive index changes.

Refractive Index and Strain Sensitivities of a Long Period Fiber Grating

A long period fiber grating （LPFG） fabricated upon the all-solid photonic bandgap fiber by CO2 laser irradiation was investigated, and its resonance wavelength was at 1335.76nm with a modulation depth of 15dB and a 3-dB bandwidth of 2.6nm. We studied its strain, temperature, and index sensor characteristics, the strain sensitivity of 0.992 pm/m was obtained by using linear fit, and the relationship between the refractive index and wavelength obeyed the distribution of quadratic function. Also, we demonstrated its temperature response was relatively insensitive （21.51 pm/~C）.

Study of magneto-optical effects in γ-Fe_2O_3/ZnFe_2O_4 nanoparticle ferrofluids, using circularly polarized light

When circularly polarized light travels through a ferrofluid film in the presence of an applied magnetic field, the transmitted light will behave as elliptically polarized light, because of magnetic birefringence and dichroism. The angular distribution of the relative intensity of the transmitted light can be obtained using a polarizer, so that the ratio of both the long and short ax- es-as well as the orientation angle of the ellipse, corresponding to the direction of the applied magnetic field--can be deter- mined, and whether the ferrofluids samples are stable during the measurement can be directly judged from the shape of the distribution curves. Thus, the ratio of the amplitudes Ax/Ay and the added phase difference A r can be resolved in the elliptically polarized light, and information on both the magnetic birefringence An and the dichroism Ak can be deduced for the ferrofluid sample. From the orientation angles of both right-handed and left-handed elliptically polarized transmitted light, the direction of the applied magnetic field can be accurately determined. Using circularly polarized light, the magnetic birefringence and dichroism of pure γ-Fe2O3 ferrofluids and γ--Fe2O3/ZnFe2O4 binary ferrofluids were studied. For the binary ferrofluids, a mod- ulating effect on the magnetic birefringence and dichroism was revealed.

All fiber sensor based on Mach-Zehnder interferometer for simultaneous measurement of temperature and refractive index

In this paper, we propose and experimentally demonstrate a compact optical fiber sensor based on a Mach-Zehnder in- terferometer （MZI） cascaded with fiber Bragg grating （FBG） for simultaneous measurement of refractive index （RI） and temperature. In order to get a proper spectrum, we discuss the effects of different structure parameters of MZI. Using the resonant wavelength of the FBG （DipFBG） and the interference dip of the MZI （Dipl）, the RI and tempera- ture of the surrounding medium can be determined. The sensor has good operation linearity. The experimental results show that the distinctive spectral sensitivities are 0.071 75 nm/℃and -91.766 67 nm/RIU （refraction index unit） for Dip1 and 0.009 09 nm/℃ for DipFBG.

Simultaneous measurement of temperature and refractive index based on a core-offset Mach-Zehnder interferometer cascaded with a long-period fiber grating

An all-fiber sensor based on a cascaded optical fiber device is proposed and demonstrated, and its sensor head is composed of a core-offset Mach-Zehnder interferometer(MZI) and a long-period fiber grating(LPFG). In the experiment, two dips shaped by the intermodulation between the interference fringe of MZI and the resonant wavelength of LPFG are monitored. Experimental results show that temperature sensitivities of two dips are 0.060 7 nm/°C and 0.056 3 pm/°C, and the refractive index(RI) sensitivities are –18.025 nm/RIU and –55.06 nm/RIU, respectively. The simultaneous measurement of the temperature and external RI is demonstrated based on the sensitive matrix. Its low fabrication cost, simple configuration and high sensitivity make this sensor have potential applications in chemical and biological sensing.

Improvement of the physical properties of poly(methyl methacrylate) by copolymerization with N-pentafluorophenyl maleimide; zero-orientational and photoelastic birefringence polymers with high glass transition temperatures

Copolymers of N-pentafluorophenyl maleimide (PFPMI) with methyl methacrylate (MMA) were synthesized by a free radical initiator, such as AIBN. The refractive indexes of the copolymers remained nearly constant (1.4970 at 532 nm) regardless of the polymer composition. These copolymers also showed high thermal stability. The orientational and photoelastic birefringence of the copolymers obtained were measured. Since both of the orientational and photoelastic birefringences of PMMA are negative whereas poly(PFPMI) exhibits positive, thus we have obtained nearly zero orientational and photoelastic birefringence polymers when the ratios of MMA/PFPMI were 91.8/8.2 and 97.0/3.0 mol%, respectively. Based on the experimental data, the ratios of MMA/PFPMI for zero birefringence were determined to be 88.9/11.1 and 93.8/6.2 mol% for orientational and photoelastic birefringence, respectively. The Tgs of corresponding copolymers were estimated to be 128 and 122 ℃.