The topic of this paper is the utilization of time for optical information processing. As clock rates in computing and communication systems increase and reach the THz border, optical techniques for signal filtering, shaping and clock distribution become attractive. We discuss the use of optics in temporal processing and consider in particular diffractive solutions. In part one of this paper, we discuss the basic concepts of temporal optics.

The topic of this presentation is the utilization of time for optical information processing. As clock rates in computing and communication systems increase and reach the THz border, optical techniques for signal filtering, shaping and clock distribution become attractive. We discuss the use of optics in temporal processing and consider in particular diffractive solutions. In this paper, we describe the use of double diffraction for implementing an ultrafast tapped-delay line.

A novel communication technique is proposed, which utilizes a set of mutually distinguishable optical patterns instead of convergent facula to transmit information. Then the capacity is increased by exploiting the optical spatial bandwidth resources. At last, we experimentally demonstrate the proposed communication technique based on four 8*8 spatial pattern signals by using lenslet array processor.

A novel latent semantic indexing (LSI) approach for content-based image retrieval is presented in this paper. Firstly, an extension of non-negative matrix factorization (NMF) to supervised initialization is discussed. Then, supervised NMF is used in LSI to find the relationships between low-level features and high-level semantics. The retrieved results are compared with other approaches and a good performance is obtained.

A fusion approach is proposed to refine the resolution of urban multi-spectral images using the corresponding high-resolution panchromatic (PAN) images. Firstly, the two images are decomposed by wavelet transformation, and five texture features are extracted from high-frequency detailed sub-images. Then a multi-characteristics fusion rule is used to merge wavelet coefficients from the two images according to the extracted features. Experimental results indicate that, comparing with the non-characteristic methods, the proposed method can efficiently preserve the spectral information while improving the spatial resolution of the urban remote sensing images.

Based on the analysis on the statistical model of speckle noise in laser underwater image, a novel speckle reduction algorithm using curvelet transform is proposed. Logarithmic transform is performed to transform the original multiplicative speckle noise into additive noise. An improved hard thresholding algorithm is applied in curvelet transform domain. The classical Monte-Carlo method is adopted to estimate the statistics of contourlet coefficients for speckle noise, thus determining the optimal threshold set. To further improve the visual quality of despeckling laser image, the cycle spinning technique is also utilized. Experimental results show that the proposed algorithm can achieve better performance than classical wavelet method and maintain more detail information.

A robust and accurate three dimensional (3D) acquisition system is presented, which is a combination of structured-light scanning and shape from silhouette. Using common world coordinate system, two groups of point data can be integrated into the final complete 3D model without any integration and registration algorithm. The mathematics model of structured-light scanning is described in detail, and the shape from silhouette algorithm is introduced as well. The complete 3D model of a cup with a handle is obtained successfully by the proposed technique. At last the measurement on a ball bearing is performed, with the measurement precision better than 0.15 mm.

A finite difference scheme based on the polynomial interpolation is constructed to solve the quasi-vector equations for optical waveguides with step-index profiles. The discontinuities of the normal components of the electric field across abrupt dielectric interfaces are taken into account. The numerical results include the polarization effects, but the memory requirement is the same as in solving the scalar wave equation. Moreover, the proposed finite difference scheme can be applied to both uniform and non-uniform mesh grids. The modal propagation constants and field distributions for a buried rectangular waveguide and a rib waveguide are presented. Solutions are compared favorably with those obtained by the numerical approaches published earlier.

The suppressing effect of the laser extraction on heat generation in Nd:YAG was investigated. The extraction efficiency could be deduced from the slope efficiency, and heat generation in Nd:YAG could be obtained with the heat model developed, which was verified by the previous experiment. The essential reasons were given to explain the change trend of heat generation under the condition of laser extraction.

Diode pumped, injection seeded single-longitudinal-mode (SLM) Nd:YAG laser is achieved through build-up time minimizing technique in Q-switching operation. Pulses with energy of 20 mJ are obtained at a repetition rate of 100 Hz. Mx2 and My2 are 1.41 and 1.38, respectively.

CO2 laser is employed to join a piece of powder metallurgical material (PMM) to a stainless steel in butt joint welding mode. The powder Ni35, as a filler powder, is used. The weld metal comes from three parts of stainless steel, powder Ni35, and Cu in W-Cu PMM. It is indicated that some parts of the W-Cu base metal are heated by laser and the metal Cu at the width of 0.06-0.12 mm from the edge is melted into the melting pool in the laser welding process. The formation of firm weld joint is just because that the melting liquid metal could fill the position occupied by metal Cu and surround the metal W granules fully. The analysis results indicate that the mechanism of the laser welding for stainless steel and W-Cu alloy is a special mode of fusion-brazing welding.

Porous silicon (PS) light-emitting diode (LED) with an ITO/PS/p-Si/Al structure was fabricated by anodic oxidation method. Photoluminescence (PL) of the PS LED was measured with a peak at 593 nm, and electroluminescence (EL) was measured with a peak at 556 nm under the conditions of 7.5-V forward bias and 210-mA current intensity. The spectral width of EL was measured to be about 160 nm.

A sigma-edged design of intraocular lens (IOL) is proposed to minimize the reflected glare images associated with the edge. The optimal sigma inverse edge is investigated when pupil diameter is 5.0 mm by the established Escudero-Sanz's wide angle model. The non-sequential ray tracing program of Zemax-EE (Zemax Development Corp., San Diego, USA) is used to investigate the sigma edge of reducing the potential for edge glare phenomena. The results show that sigma-edged design can significantly reduce the reflected glare intensity on retina if the angle of its inverse edge is taken from 20 to 70 degrees.

Based on our study on field emission from multi-walled carbon nanotubes (MWNTs), we experimentally manufactured field emission display (FED) triode with a MWNTs cold cathode, and demonstrated an excellent performance of MWNTs as field emitters. The measured luminance of the phosphor screens was 1.8*10^(3) cd/m2 for green light. The emission is stable with a fluctuation of only 1.5% at an average current of 260 'mu'A.

A radiant source with a large aperture at 5-95 Celsius degree in the wavelength bands of 8-12 'mu'm for calibrating infrared imaging systems has been designed. The effective emissivity of its flat bottom with concentric V-grooves was evaluated by the Monte-Carlo method whose correctness was tested and accuracy was discussed. The structure of the source was completed by incorporating the simulation results with the blackbody cavity effect. The source was certificated via an optical measurement system. The source can provide a consistent radiant flux with temperature uniformity of +-0.1 Celsius degree over an area of diameter of 80 mm.

A phase space model of two-dimensional (2D) Gaussian beam propagation is generalized for three-dimensional (3D) general astigmatic Gaussian beam passing through first-order optical system. The general astigmatic Gaussian beam is represented by a four-dimensional (4D) phase super-ellipsoid that defined by an associated 4*4 real matrix, then the transformation formula of the phase super-ellipsoid of the beam through first-order optical system is derived. In particular, in the phase space framework, the beam propagation factor M2 value is proved to be a ratio of phase area of real beam to ideal beam, and a novel approach for a qualitative examination of the properties of fractional Fourier transform (FRT) for the beam is also provided.

A system of two separated computer-generated holograms termed cascaded Fresnel digital holography (CFDH) is proposed and its application to hiding information is demonstrated by a computer simulation experiment. The technique is that the reconstructed image is the result of the wave Fresnel diffraction of two sub-holograms located at different distances from the imaging plane along the illuminating beam. The two sub-holograms are generated by an iterative algorithm based on the projection onto convex sets. In the application to the hiding of optical information, the information to be hidden is encoded into the sub-hologram which is multiplied by the host image in the input plane, the other sub-hologram in the filter plane is used for the deciphering key, the hidden image can be reconstructed in the imaging plane of the CFDH setup.

A deuterium cluster jet produced in the supersonic expansion into vacuum of deuterium gas at liquid nitrogen temperature and moderate backing pressures is studied by Rayleigh scattering techniques. The experimental results show that deuterium clusters can be created at moderate gas backing pressures ranging from 8 to 23 bar, and a maximum average cluster size of 350 atoms per cluster is estimated. The temporal evolution of the cluster jet generated at the backing pressure of 20 bar demonstrates a two-plateau structure. The possible mechanism responsible for this structure is discussed. The former plateau with higher average atom and cluster densities is more suitable for the general laser-cluster interaction experiments.

The optical properties of a five-level atomic system composed of a 'Lambda'-type four-level atomic and a tripod four-level atomic systems are investigated. It is found that the behaviors of electromagnetically induced transparency (EIT) and group velocity can be controlled by choosing appropriate parameters with the interacting dark resonances. In particular, when all the fields are on resonance, the slow light at the symmetric transparency windows with a much broader EIT width is obtained by tuning the intensity of the coupling field in comparison with its sub-system, which provides potential applications in quantum storage and retrieval of light.

A novel optical excitation and detection apparatus was used to investigate the characteristics of silicon micro-resonators, which was activated into vibration by a laser beam irradiation. The beam diameter of the excitation light was less than 10 'mu'm. The vibration amplitude of the resonator was detected by the interferometer with high resolution of 0.1 nm and measurement repeatability of less than 3 nm. The resonant frequency of the micro-resonator was obtained to be 8.75 kHz with full-width at half-maximum (FWHM) of 0.18 kHz. It is shown that the method is useful and reliable for measuring micro-displacement and micro-vibration of minute objects with nanometer accuracy.