Advanced Materials Research Vol. 529

Abstract: Ag-Cu nanoparticles/silicate glass composites are synthesized by twice ion-exchange and reduction treatment. The as-produced glass slides were characterized by UV–Vis spectroscopy, electron probe microanalysis (EPM) and high resolution transmission electron microscopy (HRTEM). The studies show that Ag-Cu nanoparticles aggregate on the surface of the silicate glass, which size is from 2 nm to 8 nm. The copper layer on the surface of glass matrix is about 20 m by compared to Ag layer (120 m), indicating that it is more difficult for copper ions to enter into the interior. Ag-Cu migration in glass matrix cannot be simply ascribed to a direct interaction with hydrogen, but to a more complex process involving a charge balancing mechanism during hydrogen-sodium ion-exchange.

Abstract: To obtain high energy, high efficiency Nd: glass preamplifier used in certain host device, a Nd:glass regenerative amplifier system has been designed. By adjusting the single pass gain and carefully optimizing the cavity mode, the small-scale self-focusing effect in the gain medium was effectively controlled. Maximum pulse energy of 21mJ, pulse width of 2.6ns was obtained at the repetition frequency of 1Hz, corresponding to a high optical to optical conversion efficiency of 11% and amplification ratio of 108. The pulse to pulse energy stability was < 2% rms during 2 h continous operation. The laser has a good beam quality of M2=1.5. The spectrum was measured to be at center wavelength of 1052.915nm.

Abstract: Aiming at the phenomenon that irreversible bright line and all screen black happens in the CCDs irradiated by pulsed laser, the resistance between driving electrodes and substrate was measured, damage micro-morphology of different layers in the facular area was observed, exported waveforms were detected, the damage mechanisms for CCD were analyzed in detail. The coming results show that high power pulse laser induced the ablation at different layers of CCD, increased the dark current and leakage current, which induced the failure of the device.

Abstract: With the optimized side pumped module structure, three laser diode arrays rotating symmetrically pump the Nd: Glass rod. The size of the Nd: Glass rod is Φ2 mm×75mm, with the doping concentration of 4at%. The surface of both ends of the rod coated with antireflection film at 1053nm, the rod was tilted 1.5°in order to eliminate the oscillation of amplified spontaneous emission (ASE). The seed, with energy 10μJ, operating frequency of 1Hz, pulse width 3ns, output wavelength 1053nm, through the Nd: Glass amplifiers reaches 70 times stable high-gain when the pumping power is 8.2kW and the pulse-width is 400μs. Meanwhile, the fluorescence distribution of the amplifier is homogeneous.

Abstract: This experiment uses the shower nozzle of the ring laser inside-laser coaxial powder feeding for single channel /layer, defocusing, and multi-channel lap cladding. This study investigates the influence of process parameters (such as the laser power) on forming size and surface morphology. In certain limits, the cladding layer height and width are in positive correlation with laser power and powder feeding rate, and in negative correlation with scanning velocity. When the lap coefficient is 50%, the forming quality is high.

Abstract: The relationship between the length of the objects reflections on the water surface and the following factors including the spacing of objects and people，height of objects，observers’ height and the size of wave are discussed. According to the law of light reflection, a parametric equation is established among them. Secondly, the numerical solutions of the equation can obtained by MATLAB and draw the virtual image of the material point in the water. Besides, the objects reflection on the water surface with slight wave was simulated. Finally, a detailed qualitatively analysis for the relevant factors which affect the length of reflection are made and explains the physical phenomenon successfully.

Abstract: In order to use relatively simple approach to detect the laser impulse chose the polymer organic thin-film piezoelectric sensor with high sensitivity, wide dynamic range, good frequency band response and other good characteristics, designed the subsequent amplifying and detecting circuit. The sensor converted non-electricity quantity of laser impact to measurable electricity quantity via piezoelectric effect and the amplifier circuit. After the detection system processing, the final output signal was displayed by the oscilloscope and made simple analysis of the results.

Abstract: A laser amplifier of LD pumping Nd: glass with a high beam quality and stability, which amplifies nanosecond laser pulse, has been developed in this paper. The device adopts the major technology of “LD pumping multi pass amplification together”. Beam transmission is designed with the technology of “inhibition of diffraction effect, active control and spatial filtering”.

Abstract: A low-cost, novel and robust heterodyne laser Doppler radar based on Er-doped fiber laser is presented in this paper. Reliable optical fiber components and instruments for the optical communication were used to build this system. All devices of optical circuit are connected by single-mode fibers making the system reliable and setup arrangement flexible. Spectrum estimation methods based on an efficient digital signal processing technique, fast Fourier transformation (FFT), was utilized to determine the location of the peak. Experiments were performed on a moving hard target with this developed prototype. The results are presented: the minimum velocity can be measured is below 0.5mm/s, and the resultant nonlinear of the measured curve calculated by least square method is below 100 ppm.

Abstract: A laser amplifier of LD pumping Nd: glass with a high beam quality and stability, which amplifies nanosecond laser pulse, has been developed in this paper. Under 1Hz repetition frequency, when the flat top pulse of 3 ns width and 1 nJ energy is injected as the seed pulse, the average output energy of the laser amplifier is 115.3 mJ with a net gain of 109, the energy dispersion degree of the outputting laser is no more than 2%; the modulation degree near field is less than 1.23:1.