酞菁铜薄膜的光记录特性

研究了有机染料酞菁铜（ＣｕＰｃ）真空蒸镀薄膜在可见及近红外区域的吸收光谱和光学常数，发现酞菁铜薄膜在５５０－７５０ｎｍ波长范围内具有较强的吸收，在静态测试仪上测试了酞菁铜薄膜的光存储记录特性，发现用低功率氦氖激光照样品时薄膜反射率变化较大，在酞菁记录层上覆盖金属反射层将提高写入激光的阈值能量并且增大反射率的对比度。     

偶氮侧链聚合物液晶的光学性质及其光存储应用

有机聚合物是一类非重要的非线性光学材料，它在光通信和高密度光存储等高技术领域中有良好的应用前景，文章介绍了偶氮侧链聚合物液晶的光学性质及其在光存储领域中的应用。     

亚酞菁薄膜的光谱和光存储性质研究

利用真空蒸镀法制备了一种新的三硝基溴硼亚酞菁（BTN－SubPc)薄膜。在室温下测试了该亚酞菁染料在溶液和薄膜态的吸收光谱、薄膜态的反射和透过光谱，发现该薄膜在500nm-650nm波长范围内具有优良的吸收和反射特性。在632.8nm光盘静态测试仪上测试了覆盖有金属反射层的BTN－SubPc薄膜的静态光存储性能，结果表明，用较小功率和较窄脉宽的激光辐照膜片时，可获得大于30％的反射率对比度，显示出该材料用作短波长光存储介质（特别是用于可录型数字多用光盘）的巨大潜力。     

三-α-(2,4-二甲基-3-戊氧基)溴硼亚酞菁的三阶非线性光学性质研究

应用Z扫描技术，在波长为532nm、脉宽为8ns条件下，对一种新型亚酞菁配合物三-α-(2,4-二甲基-3-戊氧基)溴硼亚酞菁的三阶非线性光学特性进行了研究，结果发现，该新化合物有较强的反饱和吸收(β=3.7×10^-10 m/W)效应和非线性自聚焦折射效应(n₂=7.2×10^-11esu)，其三阶非线性极化率χ⁽³⁾=1.1×10^-11esu.分析了溴硼亚酞菁配合物特殊的锥形分子结构和重原子溴的轴向配位等因素对其三阶非线性光学性质的重要影响. 关键词： 亚酞菁 Z扫描 三阶光学非线性     

三新戊氧基溴硼亚酞菁薄膜材料的三阶非线性光学特性

通过单光束Z扫描技术 ,在波长为 1.0 6 4μm和 5 32nm、脉宽为 38ps条件下研究了一种新的酞菁相关化合物三新戊氧基溴硼亚酞菁薄膜材料的三阶非线性光学特性。观察到在 1.0 6 4μm(离强吸收带很远 )下的双光子吸收和在 5 32nm下的反饱和吸收现象 ,并计算出了相应的非线性吸收系数。在 1.0 6 4μm下的非共振三阶非线性极化率和在 5 32nm下的共振三阶非线性极化率 χ(3 ) 分别为 6 .1× 10 - 1 2 esu和 6 .7× 10 - 1 0 esu ,显著大于相关酞菁的值。这些结果表明三新戊氧基溴硼亚酞菁薄膜材料在非线性光学方面具有潜在的应用前景。     

一种新的亚酞菁的共振三阶非线性光学性质

用简并四波混频技术研究了一种新的亚酞菁(三新戊氧基溴硼亚酞菁)的三阶非线性光学性质.测得纯固体三新戊氧基溴硼亚酞菁的三阶非线性极化率χ(3)pure和分子二阶超极化率〈γ〉分别为69×10-10esu和30×10-31esu.χ(3)pure的响应时间为20ps.并对这些结果进行了讨论     

一种新的亚酞菁的共振三阶非线性光学性质

用简并四波混频技术研究了一种新的亚酞菁(三新戊氧基溴硼亚酞菁)的三阶非线性光学性质.测得纯固体三新戊氧基溴硼亚酞菁的三阶非线性极化率χ(3)pure和分子二阶超极化率〈γ〉分别为69×10-10esu和30×10-31esu.χ(3)pure的响应时间为20ps.并对这些结果进行了讨论 关键词：     

稀土夹心双萘酞菁LB膜的非线性光学特性研究

研究了中心对称稀土夹心双萘酞菁化合物LB膜的光谱及其二阶非线性光学特性.双(四叔丁基萘酞菁)铒能制成很好的LB膜,不论在稀溶液中还是在LB膜中均主要以单体的形式存在,分子具有较大的超极化率β.由于分子为中心对称结构,所以它们的二次谐波产生机制不同于不对称萘酞菁化合物,研究证明它的二阶非线性光学特性起源于电四极子模型,其LB膜的有效二阶非线性极化率χ(2)为1.1×10-8 esu.     

双光子吸收三维数字光存储

双光子吸收三维数字光存储是实现超高密度光存储的一种重要方法,双光子吸收几率与作用光强的平方成正比,使得只有位于焦点小范围内的记录介质受到激发,双光子吸收激发的光致聚事作用,光致变色作用、光致荧光漂白、光折变等效应,引起这一小范围内记录介质的光学性质发生改变,结果能将信息写到亚微米尺度的体积单元中,实现三维数字光存储,这种双光子吸收三维数字光存储密度可达10^12Bits/cm^3。文章介绍了双光子吸收三维数字光存储的原理和进展。     

有机聚合物的非线性光学

有机聚合物是一类非常重要的非线性光学材料,这是因为它在光通信和高密度光存储等高技术领域中有良好的应用前景。有机聚合物的非线性光学性质是过去２０年来理论和实验的重要研究课题。文章在简要介绍非线性光学之后,着重论述了有机聚合物光学非线性的来源和这些材料中二阶、三阶非线性光学效应及非线性光吸收的特点。最后,简要介绍了作者在有机聚合物非线性光学研究中几个近期结果,如“全光极化、三阶光学非线性的激发态增强、     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.