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Taking laser as the heat source for ceramic sintering, 0.94K0.5Na0.5NbO3-0.06LiTaO3 ceramics with unique physical properties were prepared. Fine ferroelectric properties with remnant polarization of 18 μC/cm2 and coercive field of 18.8 kV/cm were obtained. The piezoelectric properties and density of the ceramics were d33∼120 pC/N, kp∼36.6%, TC∼420 °C, and ρ∼4.125 g/cm3. The shift of the two phase transition temperatures (tetragonal-orthorhombic phase transition temperature TO-T shifting to 100 °C from 190 °C while Curie temperature Tc shifting to 420 from 394 °C) in laser-sintered ceramics reflects large structure distortion of phase transition and Li+ substitution of high temperature phase. Orientation degree of the texture structure based on anisometric grains of submicron diameter in the ceramics was 23%. The texture structure corresponding to the fine ferroelectric properties was resulted from the mass transform in liquid phase and strictly heating directivity of laser irradiation. O2 discharge throug...

Uniform, spherical Ag nanoparticles (NPs) were produced using nanosecond excimer pulsed laser ablation of a colloid target, which had been previously prepared using silver nitrate reduction. After the irradiation experiment, the surface condition and morphology of the samples were revealed by transmission electron microscopy, and the changes in the NPs characteristics caused by different laser fluences were confirmed using optical transmission measurements with an ultraviolet–visible-infrared spectrophotometer. A considerable narrowing of the surface plasmon extinction band was achieved at 300–450 mJ laser irradiation condition, and a quantitative concept of “circularity” was put forward to estimate the degree of optimization. In addition, the effect of light-pressure explains the cause of slight collision and fusion among the nanoparticles. An analysis of these characteristics offers direct evidence of good dispersion and a change in surface shape from irregular to an ideal spherical form. A surface-enha...

This paper reports the results of developed microlens beam homogenizer for the 248 nm excimer laser. Excimer laser has a complex irradiance profile, and it is difficult to design a homogenizer for this kind of light source. We present a method to design microlens beam homogenizer according to the propagation properties of the irradiance profile. Since the intensity distribution image of excimer laser raw beam can be photographed by the laser beam analyzer, we use matlab to analyze the image and extract relevant information to calculate. With the calculated data, we simulate a virtual excimer laser source which has the same irradiance profile as the initial beam. According to the energy spatial distribution characteristics of the virtual excimer laser source, a microlens beam homogenizer is designed. The designed microlens homogenizer has been fabricated and tested. Measurements of the irradiance profile is presented and compared to the ideal design. After shaping and homogenization, a highly uniform beam ...

A new method of synthesis Ag/Au core/shell nanostructure with ultraviolet (UV) excimer laser was studied. It was found Ag/Au core/shell nanostructures with spherical shell could be prepared by UV excimer laser which is obviously confirmed by high resolution transmission electron microscopy. The surface plasma resonance of this nanostructure can be tuned by controlling thickness of the Au shell. Simulation based on Mie theory was in agreement with the result of the experiments. Moreover, it is indicated the Ag/Au core/shell nanostructure has excellent activity in surface-enhanced Raman scattering. This Ag/Au core/shell nanostructure may be applied to high sensitive trace detection in the future.

In texturing dentin surface by KrF laser with the fluences of 200–800 mJ/cm2, it is observed the irradiated surface topography has different characteristics with that irradiated under high fluence above 1000 mJ/cm2 reported in previous studies. The formation threshold fluence of the microstructure consisted of erected microcylinders was determined at 400 mJ/cm2. By scanning electron microscopy including fine examination of a single microstructure unit under high magnification, the microstructure formation and evolution tending to the fashion of high fluence were given. Analysis of the ablation details captured by high-speed photography confirmed the development mechanism of the texturing microstructure. Raman analysis showed the composition of the laser textured dentin underwent changes. Although the texturing is related to the characteristics of the dentin tissue, laser parameters play a decisive role in the controlling of the shape and the height of the three-dimensional microstructure. The combination of our work and the previous work by Sivakumar et al. [J. Laser Appl. 18(4), 330–333 (2006) and Lasers Med. Sci. 21, 160–164 (2006)] demonstrates laser fabrication of the three-dimensional microstructure with different topography features on dentin surface is controllable.