A novel morphological filtering algorithm is proposed for suppressing speckle noise in images. The algorithm employs directional morphological close-open and open-close operations, then computing the membership of the filtered versions’ every pixel according to the designed fuzzy rule. The final filtered image is composed of all the pixels with corresponding maximal membership. The validity of the algorithm is demonstrated.

Stable mode-locking in a diode-pumped Yb:YAG laser was obtained with a very fast semiconductor saturable absorber mirror (SESAM). The pulse width was measured to be 4 ps at the central wavelength of 1047 nm. The average power was 200 mW and the repetition rate was 200 MHz.

A passively Q-switched diode pumped Yb:YAG microchip laser with Cr^(4+):YAG saturable absorber mirror is reported. The TEM00 laser pulses are obtained with 1.7-μJ pulse energy, 15-ns pulse width, 0.11-kW peak power, and a repetition rate of 2.2 kHz at 1049 nm. The doped concentration and dimension of Yb:YAG microchip crystal are 10 at.-% and Ф5 × 0.6 mm^(2), respectively.

A set of phosphate glasses with different amounts of Al~~(2)O~~(3), Na~~(2)O, La~~(2)O~~(3) and AlF~~(3) contents were prepared to search for a phosphate glass which is suitable for ion-exchange process. Based on chemical durability test results and spectroscopic properties, a glass with excellent chemical durability and good spectroscopic properties is developed for ion-exchange process. The emission cross section of Er^(3+) in this glass is calculated to be 0.72×10^(-20) cm^(2) by McCumber theory. The planar waveguide with three modes at 632.8 nm and one mode at 1540 nm can be realized by 335 ℃ 3 hours ion-exchange in 5%AgNO~~(3)+95%KNO~~(3) molten salt.

The Yb^(3+)/Er^(3+) co-doped TeO~~(2)-WO~~(3)-ZnO glasses bubbling with different times were prepared. The infrared (IR) transmission spectra, emission spectra and fluorescence lifetime of Er^(3+) at 1.5μm were measured. The quench effects of OH groups on emission intensity of Er^(3+) at 1.5 μm as well as the relationships between fluorescence decay rate and OH group content were investigated. The constant k~~(OH-Er), which represents the strength of the interactions between Er^(3+) ions and OH groups, is approximately 17.0×10^(-20) cm^(4)/s, and is comparable to that for Er^(3+) in Yb^(3+)/Er^(3+) co-doped phosphate glasses.

Coupling theory is employed to analyze coupling gain and a new optical system is proposed for image edge enhancement, in which the ordinarily discarded background light is recycled as a pump source to amplify the signal light. We demonstrate the principle of optical correlation and compare the discrimination capability of two kinds of correlators by computer simulation. The results show that edge enhancement preprocessing can improve discrimination capability effectively.

The conversion efficiency of THG on the flattened Gaussian and Gaussian beams is obtained in detail numerical stimulation for CsLiB~~(6)O~~(10). The conversion efficiencies of 86.7% and 96% of the flattened Gaussian are larger than those of Gaussian beams of 72.6% and 88% under type I and type II(1) phase matching. The efficiencies affected by the pump intensity, polarization rate, crystal lengths and orders of the flattened Gaussian beams were presented.

An optical parametric oscillator (OPO) based on periodically-poled lithium niobate (PPLN) and pumped by 1064.2-nm laser is demonstrated, which can be conveniently tuned by the means of changing its operating temperature. The parameters of the set-up and experimental results are introduced in this paper. We adjusted the operating temperature from 80 to 250 ℃, the output wavelength shifted from 1485.4 to 1540.7 nm. The average of the shifts is 0.33 nm/℃.

A reliable target-triggering plasma shutter was applied to second harmonic generation (SHG) of AgGaSe~~(2) crystal with a TEA CO~~(2) laser. Under normal air pressure, argon charged plasma shutter was triggered by focusing beam companying with a pair of adjustable metal targets. Conversion efficiency was enhanced by 3.3 times and the maximal efficiency 9.3%, with 1.4-mJ second harmonic energy was obtained. Finally, crystal damage was discussed together with previous work.

Two-dimensional (2D) triangular void channel photonic crystals with different lattice constants stacked in two different directions were fabricated by using femtosecond laser micro-explosion in solid polymer material. Fundamental and higher-order stop gaps were observed both in the infrared transmission and reflection spectra. There is an approximately linear relationship between the gap position and the lattice constant. The suppression of the fundamental gap is as high as 70% for 24-layer structures stacked in the Γ-M direction.

The quantum dynamic behavior of the system composed of V-type three-level atomic Bose-Einstein condensate (BEC) interacting with two-mode coherent light field has been studied. The results show that the atoms of V-type three-level atomic BEC, which are excited to higher-level states under the action of light field, still keep their properties of coherent states. It demonstrates theoretically that two-mode atomic laser may be prepared by V-type three-level atomic BEC.

A new direction recognizing and subdividing method for moire (interference) fringes is presented. By setting two certain thresholds, counting errors caused by direct voltage excursion are avoided. Counting and direction recognizing are discussed in detail. Experimental results are given. The better adaptability and large subdivision number are the good quality of this method.

To improve the optical storage performance, Sn was doped into Ge~~(2)Sb~~(2)Te~~(5) phase change thin films. The optical and thermal properties of Sn-doped Ge~~(2)Sb~~(2)Te~~(5) film were investigated. The crystal structures of the as-sputtered and the annealed films were identified by the X-ray diffraction (XRD) method. The differential scanning calorimeter (DSC) method is used to get the crystallization temperature and crystallization energy (Ea). It was found that proper Sn-doping could highly improve storage performance of the Ge~~(2)Sb~~(2)Te~~(5) media.

It is reported that the wave-front aberration produced by atmosphere disturbance can be compensated with nonlinear optics phase conjugate technology. The distance of laser propagating in atmosphere is up to 1.27 km away. The result shows that SBS phase conjugating beam energy can be focus in a little area on target. And the biggest energy of phase conjugating beam on target is up to 142 mJ.

The line of sight (LOS) wind velocity can be determined from the incoherent Doppler lidar backscattering signals. Noise and interference in the measurement greatly degrade the inversion accuracy. In this paper, we apply the discrete wavelet denoising method by using biorthogonal wavelets and adopt a distancedependent thresholds algorithm to improve the accuracy of wind velocity measurement by incoherent Doppler lidar. The noisy simulation data are processed and compared with the true LOS wind velocity. The results are compared by the evaluation of both the standard deviation and correlation coefficient.The results suggest that wavelet denoising with distance-dependent thresholds can considerably reduce the noise and interfering turbulence for wind lidar measurement.