On the basis of Kolmogorov's theorem, the physical meanings of beams' correlation function on received plane are extended. Approximate formula of channels' across correlation coefficient is deduced from multiple beams through atmosphere. And the scintillation variance of multiple beams is also induced. The result shows along with the channels close to one another, the correlation coefficient increases, and so does the scintillation variance. When the channels completely combine, the scintillation variance of multiple channels is with no difference from that of one channel.

A model complex optical potential rewritten by the conception of bonded atom, which considers the overlapping effect of electron cloud, is employed to calculate the total (elastic + inelastic) cross sections with simple molecules (N_(2), O_(2), NO_(2), NO, N_(2)O) consisting of N & O atoms over an incident energy range of 100 - 1600 eV by the use of additivity rule at Roothaan-Hartree-Fock level. In the study, the complex optical potential composed of static, exchange, correlation polarization plus absorption contributions firstly uses bonded-atom conception. The qualitative results are compared with experimental data and other calculations wherever available and good agreement is obtained. The total cross sections of electronmolecule scattering above 100 eV can be successfully calculated.

We investigate the emission spectra of a Ξ-type three-level atom interacting with a single-mode optical field in an ideal cavity filled with a Kerr medium and discuss the structure of emission spectrum when the optical field is initially in a pure number state and a coherent state, respectively. It is shown that the structure of emission spectrum depends not only on the photon number distribution, but also on the strength of incident field and the coupling of Kerr medium to the field.

We report the adaptive compensation experiment of polarization mode dispersion (PMD) for 10-Gb/s non return-to-zero (NRZ) and return-to-zero (RZ) optical communication systems using a two-stage PMD compensator and the monitoring technique based on degree of polarization (DOP) feedback-signals. The DOP monitor has its advantages of bit-rate independent and modulation format independent. The twostage compensator has the capacity of compensation for the first- and second-order PMD. The compensated differential group delay (DGD) is up to 80 ps, and compensated principal state of polarization rotation rate is 20 ps. The time used for compensation is less than 1 second.

The supercontinuum (SC) generation in conventional dispersion-shifted fiber (DSF) at the repetition rate of 10 GHz with a three-stage compressed gain-switched distributed feedback (DFB) laser as pump source was demonstrated. A novel SC pulse source with a bandwidth up to 120 nm was obtained. At the same time, the stable, narrow pulses with pulsewidth of 9.2 ps and time-bandwidth product of 0.46 were filtered out across the whole SC bandwidth.

In this paper, two new similarity measure methods based on set theory were proposed. Firstly, similarity measure of two sets based on set theory and set operation was discussed. This principle was used to spectral vectors, and two approaches were proposed. The first method was to create a spectral polygon corresponding to spectral curve, and similarity of two spectral vectors can be replaced by that of two polygons. Area of spectral polygon was used as quantification function and some effective indexes for similarity and dissimilarity were computed. The second method was to transform the original spectralvector to encoding vector according to absorption or reflectance feature bands, and similarity measure was conducted to encoding vectors. It proved that the spectral polygon-based approach was effective and can be used to hyperspectral RS image retrieval.

Based on geometrical facial features and image segmentation, we present a novel algorithm for automatic localization of human eyes in grayscale or color still images with complex background. Firstly, a determination criterion of eye location is established by the prior knowledge of geometrical facial features. Secondly, a range of threshold values that would separate eye blocks from others in a segmented face image (i.e., a binary image) are estimated. Thirdly, with the progressive increase of the threshold by an appropriate step in that range, once two eye blocks appear from the segmented image, they will be detected by the determination criterion of eye location. Finally, the 2D correlation coefficient is used as a symmetry similarity measure to check the factuality of the two detected eyes. To avoid the background interference, skin color segmentation can be applied in order to enhance the accuracy of eye detection. The experimental results demonstrate the high efficiency of the algorithm and correct localization rate.

A new method for natural color image segmentation using integrated mechanism is proposed in this paper. Edges are first detected in term of the high phase congruency in the gray-level image. K-mean cluster is used to label long edge lines based on the global color information to estimate roughly the distribution of objects in the image, while short ones are merged based on their positions and local color differences to eliminate the negative affection caused by texture or other trivial features in image. Region growing technique is employed to achieve final segmentation results. The proposed method unifies edges, whole and local color distributions, as well as spatial information to solve the natural image segmentation problem.The feasibility and effectiveness of this method have been demonstrated by various experiments.

A new method for analyzing the phase distributions of deformed grating images on the surface of threedimensional (3D) object to obtain its shape information has been presented. In the conventional technique, Fourier transform profilometry (FTP), there is an intrinsic problem of extracting the fundamental frequency component if the deformation of the grating pattern is either considerable or complicated, which will definitely bring bad influence to the analysis’ accuracy. That means FTP is not appropriate to deal with the complex surfaces of 3D objects. The approach that we here introduce to solve this problem is to utilize Gabor wavelet transform (GWT), a tool excelling for its multiresolution in time-frequency domain, to analyze the phase distributions.

A new 1×4 buried optical power splitter with curved Y-junction structure has been successfully designed by a beam propagation method (BPM) software and fabricated by two-step ion-exchange in glass. The optical qualities of the device are favorable in comparison with that obtained with dry etching fabrication techniques.

Noble gases (argon, krypton, and xenon) are puffed into vacuum through a nozzle to produce clusters for studying laser-cluster interactions. Good estimates of the average size of the argon, krypton and xenon clusters are made by carrying out a series of Rayleigh scattering experiments. In the experiments, we have found that the scattered signal intensity varied greatly with the opening area of the pulsed valve. A new method is put forward to choose the appropriate scattered signal and measure the size of Kr cluster.

A continuous wave (CW) Nd:YAG infrared laser at 1319 nm is reported in this paper. The energy level of 1319-nm wave was analyzed. The repression of 1064-nm lasing and enhancement of 1319-nm output power were discussed. Mirror coating and cavity structure were studied and a maximum CW output power of 43 W at 1319 nm was achieved in experiments.

Fabrication technology of the Yb^(3+):Er^(3+) co-doped glass samples is introduced. Photoluminescence (PL) characteristics of a single sample were experimentally investigated. The PL peak intensities of two samples in series were measured and discussed. The results show that the PL peak intensities of two samples in series depend on pump manners and arrangement of the samples. The better amplification ability can be obtained by two samples in series doped with low-concentration ytterbium instead of a single sample doped with high-concentration ytterbium.

In this paper, the growth and characteristics of ZnCdSe/ZnSe quantum wells (QWs) prepared on ZnOSi (111) templates are reported. An oriented ZnO thin film with a smooth surface was employed to be the buffer layer for the ZnCdSe/ZnSe QWs growth. Scanning electron microscopy (SEM) patterns showed that the ZnO buffer layer improved the smoothness of the ZnCdSe/ZnSe sample. Up to the 3rd longitudinal optical phonon of Zn0:56Cd0:44Se observed in Raman spectra suggests that the crystalquality of ZnCdSe/ZnSe QWs is reasonably good. The influence of quantum confinement effect on exciton characters of the QWs was also demonstrated.

We report the numerical observation of discrete spatial solitons in a periodically poled lithium niobate waveguide array by applying an electrical field through electro-optical effect. We show that discrete spatial soliton can be controlled by applied voltage in the periodically poled lithium niobate.

In this paper, a numerical simulation of the traditional graded distributed Bragg reflector (DBR) and a design of the novel DBR with short period superlattices (SPSs DBR) used by vertical cavity surface emitting laser (VCSEL) are reported. First, the optical characteristic matrix of the graded DBRs is derived using the theories of thin film optics. Second, its reflective spectrum is numerical simulated and it is found that the simulative results are similar with the experimental data. The difference of the cavity mode position between the experimental and simulative data is discussed. Finally, based on the simulative results of graded DBR, a novel DBR with 4.5-pair GaAs/AlAs SPSs is designed, and its reflective spectrumis numerical simulated and analyzed.

We have fabricated a light emitting diode using a p-type conducting polyaniline layer deposited on a n-type porous silicon (PS) layer. The contact formed between a p-type conducting polyaniline layer and a n-type PS wafer has rectified behaviour demonstrated clearly by the I-V curves. The series resistance Rs in the p-type conducting polyaniline/n-PS diode is reduced greatly and has a lower onset voltage compared with ITO/n-PS diode. The PS has an orange photoluminescence (PL) band after coating with polyaniline. Visible electroluminescence (EL) has been obtained from this junction when a forward bias is applied. The emission band is very broad extending from 600 - 803 nm with a peak at 690 nm.

In this paper, we first present a full numerical simulation for the trapping and retrieval procedure of eight continuing “1” Guassian pulses (i.e., “11111111”) in the electromagnetically induced transparency (EIT) medium. This simulation shows that an EIT medium has the ability to store multiple light pulses in a shape-preserving way. And we also, for the first time, give the formula evaluating the maximum number of pulses that can be stored by an EIT medium at one time. This work reveals a new possible way to the reversible storage of the photonic information.

A high power laser system delivering a 20-TW, 0.5 - 0.8 ps ultra-short laser pulse and a 20-J, 500-ps long pulse simultaneously in one shot is completed. This two-beam laser operates at the wavelength of 1053 nm and uses Nd doped glass as the gain media of the main amplification chain. The chirped-pulse amplification (CPA) technology is used to compress the stretched laser pulse. After compression, the ultrashort laser pulse is measured: energy above 16.0 J, S/N contrast ratio ~ 10^(5) : 1, filling factor ~>52.7%. Another long pulse beam is a non-compressed chirped laser pulse, which is measured: energy ~ 20 J, pulse duration 500 ps. The two beams are directed onto the target surface at an angle of 15°.

Operating a laser diode in an external cavity, which provides frequency-selective feedback, is a very effective method to tune the laser frequency to a range far from its free running frequency. For the Ca atomic Ramsey spectroscopy experiment, we have constructed a 657-nm laser system based on the Littman-Metcalf configuration with a 660-nm commercial laser diode. Continuously 10-GHz tuning range was achieved with about 100-kHz spectral linewidth, measured with beat-note spectrum of two identical laser systems.