2008, 6(5) Column
Chinese Optics Letters 第6卷 第5期
Ab initio multi-reference configuration interaction of the low-lying states of the AsP moleculeDownload:947次
Nine low-lying electronic states of the AsP molecule, including \Sigma+, \Pi, and \Delta symmetries with singlet, triplet, and quintet spin multiplicities, are studied using multi-reference configuration interaction method. The potential energy curves and the spectroscopic constants of these nine states are determined, and compared with the experimental observed data as well as other theoretical works available at present. Three quintet states are reported for the first time. Furthermore, the analytical potential energy functions of these states are fitted using Murrell-Sorbie function and least square fitting method.
AsP分子 激发态 势能曲线 解析势能函数 光谱常数 020.0020 Atomic and molecular physics 300.6390 Spectroscopy, molecular 300.6360 Spectroscopy, laser 300.6210 Spectroscopy, atomic Second harmonic 423-nm laser generated by BIBO crystal for calcium optical frequency standardDownload:681次
Calcium is one prospective element for the modern optical frequency standard. The 423-nm transition line of calcium atoms has been widely used in laser slowing and laser cooling, the precise spectrum measurement, and the magnetic optical trapping (MOT). However, there is no any available commercial diode laser working at this wavelength. We built a 423-nm laser based on extra bow-tie cavity and by using a Brewster-cut uncoated BIBO (BiB3O6) crystal, which worked at room temperature, with conversion efficiency of 3.75%, and a potential up to 20%.
光学频率标准 BIBO晶体 钙原子 020.0020 Atomic and molecular physics 140.0140 Lasers and laser optics 190.0190 Nonlinear optics Quick single-photon detector with many avalanche photo diodes working on the time divisionDownload:571次
Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system. A new idea is put up to design a quick single-photon detector. This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs). All of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal. The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector. The single-photon prompt detection can come true for high repetition-rate pulses. The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.
单光子探测器 雪崩二极管 量子通信 量子密钥分配 码率 时分模式 040.5160 Photodetectors 060.4510 Optical communications 230.5160 Photodetectors 270.5570 Quantum detectors For breaking through the sensitivity limitation of conventional surface plasmon resonance (SPR) biosensors, novel highly sensitive SPR biosensors with Au nanoparticles and nanogratings enhancement have been proposed recently. But in practice, these structures have obvious disadvantages. In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parameters on the performance is investigated by using rigorous coupled wave analysis (RCWA). Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters. The results indicate that significant sensitivity increase is associated with localized surface plasmons (LSPs) excitation mediated by nanoholes. Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves’ width are obtained simultaneously under optimized structural parameters.
表面等离子体共振传感器 纳米小孔 灵敏度增强 平面波耦合算法(RCWA) 130.3120 Integrated optics devices 230.3990 Micro-optical devices 040.1880 Detection Design of Raman-parametric fiber amplifier for wavelength division multiplex transmission systemDownload:537次
We optimize the novel configuration of a hybrid fiber amplifier-Raman assisted-fiber-based optical parametric amplifier (R-FOPA), in which the parametric gain and Raman gain profiles are combined to achieve a flat composite gain profile. The pump powers and the fiber length in the hybrid amplifier are effectively optimized by genetic algorithm (GA) scheme. The optimization results indicate that the R-FOPA can achieve a 200-nm flat bandwidth spectrum with the gain of 20 dB and ripple of less than 4 dB.
参量放大器 拉曼散射 遗传算法 190.4970 Parametric oscillators and amplifiers 290.5860 Scattering, Raman Based on the property analysis of interferential multispectral images, a novel compression algorithm of partial set partitioning in hierarchical trees (SPIHT) with classified weighted rate-distortion optimization is presented. After wavelet decomposition, partial SPIHT is applied to each zero tree independently by adaptively selecting one of three coding modes according to the probability of the significant coefficients in each bitplane. Meanwhile the interferential multispectral image is partitioned into two kinds of regions in terms of luminous intensity, and the rate-distortion slopes of zero trees are then lifted with classified weights according to their distortion contribution to the constructed spectrum. Finally a global rate-distortion optimization truncation is performed. Compared with the conventional methods, the proposed algorithm not only improves the performance in spatial domain but also reduces the distortion in spectral domain.
图像压缩 干涉多光谱图像 部分SPIHT 率失真优化截取 100.0100 Image processing 100.2000 Digital image processing 070.0070 Fourier optics and signal processing 280.0280 Remote sensing and sensors The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix. Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image. By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then. Gradient-loading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading. Compared with the approach using least square filtering, its peak signal-to-noise ratio (PSNR) is improved from 3.18 to 6.46 dB, while the computing time is reduced to 1/2-1/3. Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.
旋转运动模糊 图像复原 梯度加载 循环矩阵 100.0100 Image processing 100.3020 Image reconstruction-restoration 100.5760 Rotation-invariant pattern recognition Region-based fusion of infrared and visible images using nonsubsampled contourlet transformDownload:699次
With the nonsubsampled contourlet transform (NSCT), a novel region-segmentation-based fusion algorithm for infrared (IR) and visible images is presented. The IR image is segmented according to the physical features of the target. The source images are decomposed by the NSCT, and then, different fusion rules for the target regions and the background regions are employed to merge the NSCT coefficients respectively. Finally, the fused image is obtained by applying the inverse NSCT. Experimental results show that the proposed algorithm outperforms the pixel-based methods, including the traditional wavelet-based method and NSCT-based method.
图像融合 非采样Contourlet变换 区域分割 100.0100 Image processing 350.2660 Fusion 110.3080 Infrared imaging Using traditional five-interferogram algorithm to unwrap phase for length measurement, the phase steps must be equal to \pi/2 exactly, but it is almost impossible to achieve in nanometer positioning technique. Aiming to overcome this defect of traditional five-interferogram algorithm, an improved five-interferogram algorithm is presented. This improved algorithm not only keeps the high accuracy of traditional five-interferogram algorithm, but also does not need absolute equal step to unwrap phase. Instead, this algorithm only needs measuring phase-shifting. With the numerical simulation, the improved five-interferogram algorithm shows high accuracy, high reliability, and feasibility in practice. It is very valuable for accurate length measurement with Fizeau interferometer and Fabry-Perot interferometer.
多光束干涉 五幅相依算法 精密测长 相位误差 120.3180 Interferometry 120.2650 Fringe analysis 120.2230 Fabry-Perot 120.3930 Metrological instrumentation 120.3940 Metrology Application of multi-phase particle swarm optimization technique to retrieve the particle size distributionDownload:820次
The multi-phase particle swarm optimization (MPPSO) technique is applied to retrieve the particle size distribution (PSD) under dependent model. Based on the Mie theory and the Lambert-Beer theory, three PSDs, i.e., the Rosin-Rammer (R-R) distribution, the normal distribution, and the logarithmic normal distribution, are estimated by MPPSO algorithm. The results confirm the potential of the proposed approach and show its effectiveness. It may provide a new technique to improve the accuracy and reliability of the PSD inverse calculation.
粒径分布 非独立模式 多相微粒群算法 290.2200 Extinction 120.5820 Scattering measurements 300.6360 Spectroscopy, laser An integrated optical electric field sensor based on a Mach-Zehnder interferometer with the telescopic dipole is designed and fabricated, and its electrodes are segmented and connected with a telescopic dipole. The measured results show that when the frequency response is from 10 kHz to 6 GHz with the antenna length of 55 mm, the minimum detectable electric field of 20 mV/m can be obtained, and the linear dynamics range can reach 90 dB at 250 MHz.
电场传感器 拉杆天线 集成光学 电磁兼容性 130.6010 Sensors 130.3120 Integrated optics devices 230.4110 Modulators Testifying experiment of the multi-pulse phenomena of capillary discharge soft-X-ray laserDownload:525次
In a capillary discharge experiment for the neon-like argon lasing, we have proposed an experimental scheme to verify that the multi-spike of X-ray diode (XRD) signal is a multi-pulse laser or is a reflection of the laser pulse in the XRD. The ceramic capillary has an inner diameter of 3 mm and a length of 200 mm. At the gas pressure of 28 Pa and discharge current of 27 kA, stable lasing has been realized. The experimental results prove that the multi-spike of XRD signal is a reflection of the electromagnetic signal produced by the laser pulse in the XRD. The improved electrocircuit scheme of the XRD to minimize the reflection phenomena is also found.
软X射线激光 毛细管放电 软X射线探测 多脉冲激光 电磁波反射信号 140.7240 UV, EUV, and X-ray lasers 350.5400 Plasmas 340.7480 X-rays, soft x-rays, extreme ultraviolet (EUV) Boundary coupled dual-equation numerical simulation on mass transfer in the process of laser claddingDownload:693次
The coupled numerical simulation on fluid flow, heat transfer, and mass transfer in the process of laser cladding is undertaken on the basis of the continuum model. In the simulation of mass transfer in the laser molten pool, the concentration distribution in the regions on different sides of the interface between cladding layer and substrate is calculated separately and coupled at the co-boundary. The non-equilibrium solute partition coefficient is obtained from equilibrium solute partition coefficient according to the Sobolev model. By using the developed software which is based on the commercial software PHOENICS 1.4, the distribution of Fe in laser molten pool in an experiment of cladding Stellite 6 on 12CrMoV is calculated. The obtained results well coincide with the experimental ones.
激光熔覆 浓度场 数值模拟 溶质非平衡分配系数 140.0140 Lasers and laser optics 140.3390 Laser materials processing 000.3860 Mathematical methods in physics We propose a diode end-pumped passively mode-locked Nd:Gd0.42Y0.58VO4 (Nd:GdYVO4 laser at 1064 nm using a GaAs absorber grown at low temperature as the output coupler. Stable continuous-wave (CW) mode locking with a 5.1-ps pulse duration at a repetition rate of 113 MHz is obtained. The maximum average output power is 2.29 W at the incident pump power of 12 W with the slope efficiency of about 24.8%.
Nd:Gd0.42Y0.58VO4 晶体 低温生长GaAs 连续锁模 半导体激光端面泵浦激光器 140.0140 Lasers and laser optics 140.2020 Diode lasers We report a high-power thin Nd:YAG slab laser with slab dimension of 1 mm \time 10 mm \time 60 mm partially edge-pumped by diode laser arrays. Passive Q-switching is achieved with a Cr4+:YAG microchip adopted as the saturable absorber mirror. The pulse duration is around 10 ns while the pulse repetition rate is higher than 10 kHz. The average output power of 70 W is obtained with a slope efficiency of 36%. The diffraction limited beam quality in the thickness direction is obtained by controlling the pump beam diameter inside the slab. The laser head is very compact with size of only 60 \time 70 \time 150(mm).
固体激光器 被动调Q 热效应 光束质量 140.3540 Lasers, Q-switched 140.3480 Lasers, diode-pumped 230.7400 Waveguides, slab Conductively cooled all-solid-state zigzag slab laserDownload:1339次
A diode pumped, Q-switched Nd:YAG zigzag slab laser is developed using passive conduction cooling. Flat-flat and unstable resonators are adopted in this experiment. The 150-mJ multi-mode and 100-mJ single-mode laser outputs with pulse width of 10 ns are achieved, corresponding to optical efficiencies of 19% and 13%, respectively. The experimental result demonstrates that the laser has the property of compact structure, high efficiency, reliability, and high beam quality. The design of laser has a potential application in space environment.
全固态激光器 Q开关激光器 传导冷却 140.3580 Lasers, solid-state 140.3480 Lasers, diode-pumped 140.3540 Lasers, Q-switched A study on the best irradiation dose of X-ray for Hep-2 cells by Fourier transform infrared spectroscopyDownload:571次
Fourier transform infrared spectroscopy (FTIR) was employed to study the human epidermis larynx carcinoma cell lines (Hep-2) which were irradiated by different doses of X-ray. The results show that (1) the irradiation of X-ray damages the structure of the CH3 groups of the thymine in DNA, which restrains the reproduction of Hep-2 cells effectively, (2) the 8 Gy dose of X-ray irradiation changes the framework and the relative contents of some proteins, lipids and the nucleic acid molecules intercellular in the greatest degree, and (3) the 8 Gy dose of X-ray irradiation is the best irradiation dose for lowering the degree of the cancerization of Hep-2 cells according to the criteria for the degree of the cancerization reported recently. Meanwhile, the apoptosis of these cells were detected by using flow cytometry (FCM) primarily. It shows that the apoptotic ratio of the Hep-2 cells depends on the irradiation dose to some extent, but is not linearly. And the apoptotic ratio of the 12 Gy dose group is the maximum (20.36%), but the apoptotic ratios of the 2 to 8 Gy dose groups change little.
傅立叶变换红外光谱 X射线 放射剂量 人上皮样喉癌细胞株 300.6300 Spectroscopy, Fourier transforms 040.3060 Infrared 340.7480 X-rays, soft x-rays, extreme ultraviolet (EUV) 170.1530 Cell analysis The Kerr nonlinearity of a left-handed material is analyzed in a four-level atomic system. It is shown that, due to the effect of quantum interference, a large enhanced Kerr nonlinearity accompanied by vanishing absorption can be realized via choosing appropriate parameters in this negative refraction atomic medium. It not only shows the large nonlinearity but also acts as the phase and amplitude compensating effects.
负折射 原子介质 克尔非线性增强 190.0190 Nonlinear optics 270.0270 Quantum optics The surfaces and refractive index of crystalline lens play an important role in the optical performance of human eye. On the basis of two eye models, which are widely applied at present, the effect of lens surfaces and its refractive index distribution on optical imaging is analyzed with the optical design software ZEMAX (Zemax Development Co., San Diego, USA). The result shows that good image quality can be provided by the aspheric lens surfaces or (and) the gradient-index (GRIN) distribution. It has great potential in the design of intraocular lens (IOL). The eye models with an intraocular implantation are presented.
视光学 人眼模型 光学设计 晶状体 330.7320 Vision adaptation 170.4460 Ophthalmic optics and devices 220.1250 Aspherics 110.2760 Gradient-index lenses Pseudo working-point control measurement scheme for acoustic sensitivity of interferometric fiber-optic hydrophonesDownload:650次
A novel pseudo working-point control measurement scheme for the acoustic sensitivity of interferometric fiber-optic hydrophones is described and demonstrated. The measurement principle is introduced in detail. An experimental system, which interrogates an interferometric fiber-optic hydrophone with this method, is designed. The acoustic pressure phase sensitivity of the fiber-optic hydrophone is measured over the frequency range of 20-2500 Hz. The measured acoustic sensitivity is about -156.5 dB re 1 rad/\muPa with a fluctuation lower than +-2 dB, which is in good agreement with the results obtained by the method of phase generated carrier. The experimental results testify the validity of this new method which has the advantages of no electric elements in the sensing head, the simplicity of signal processing, and wide working bandwidth.
光纤干涉仪 光纤传感器 光纤水听器 声压灵敏度 外差 零差 060.2370 Fiber optics sensors 060.2420 Fibers, polarization-maintaining 230.1150 All-optical devices Intrinsic stress analysis of sputtered carbon filmDownload:631次
Intrinsic stresses of carbon films deposited by direct current (DC) magnetron sputtering were investigated. The bombardments of energetic particles during the growth of films were considered to be the main reason for compressive intrinsic stresses. The values of intrinsic stresses were determined by measuring the radius of curvature of substrates before and after film deposition. By varying argon pressure and target-substrate distance, energies of neutral carbon atoms impinging on the growing films were optimized to control the intrinsic stresses level. The stress evolution in carbon films as a function of film thickness was investigated and a void-related stress relief mechanism was proposed to interpret this evolution.
磁控溅射 C膜 内压力 230.4040 Mirrors 310.6870 Thin films, other properties 0.532-\mum laser conditioning of HfO2/SiO2 third harmonic separator fabricated by electron-beam evaporationDownload:753次
The 0.532-\mum laser conditioning of HfO2/SiO2 third harmonic separator fabricated by electron-beam evaporation (EBE) was studied. The laser induced damage threshold (LIDT) of the separator determined by 1-on-1 test is 9.1 J/cm2 and it is 15.2 J/cm2 after laser conditioning determined by raster scanning. Two kinds of damage morphologies, taper pits and flat bottom pits, are found on the sample surface and they show different damage behaviors. The damage onset of taper pits does not change obviously and the laser conditioning effect is contributed to the flat bottom pits, which limits the application of laser conditioning.
三倍频分离膜 激光预处理 损伤阈值 光栅式扫描 140.3330 Laser damage 310.6870 Thin films, other properties The femtosecond laser induced void array inside Al2O3 crystals was discussed. The void array was formed spontaneously under the irradiation of a single beam of infrared femtosecond laser which was focused at a fixed point inside the Al2O3 crystal sample. It was found that the regular voids only could be fabricated near the sample surface, which was different from the situation in CaF2 single crystal reported before. The possible mechanism of the phenomena was also discussed.
微米点阵 飞秒激光 氧化铝晶体 140.7090 Ultrafast lasers 320.7130 Ultrafast processes in condensed matter, including semiconductors 动态信息
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