The thermal deformation of silica glass reflectors employed in high-power laser systems has emerged as a critical issue, imposing limitations on the scalability of lasers to achieve high average power and high beam quality. Water-cooling is the most effective and commonly employed method for reducing thermal deformation. However, it is challenging to create embedded microchannels for water-cooling in silica glass by conventional processing methods. In this study, we demonstrate a novel method for fabricating silica glass microchannel reflectors by combining glass slurry UV-curing with 3D printing of polymeric microchannels. The glass slurry consists of SiO2 nanoparticles and organic resins, which can be UV-cured and subsequently transformed into fused silica glass through heat treatment. During the UV-curing process, the 3D printed polymeric microchannel structure is embedded within the glass slurry. Subsequently, in the heat treatment process, the polymeric microchannel structure is removed, leaving behind the corresponding hollow cavity. The photocurable resin used for printing microchannels is optimized to ensure a crack-free sample. The sintered sample shows an isotropic shrinkage of 28%. Microchannel structures with different shapes are created. The water tightness of the fabricated reflectors is validated by injecting red ink into the microchannels.
The effects of femtosecond laser (wavelength 1035nm, pulse duration 400 fs, pulse repetition rate 1kHz) on the material removal threshold of superalloy was experimentally investigated, specifically the influence of pulse number irradiated on the threshold of superalloy. Irregular bulge structures were found at the bottom of ablation holes. Two sets of material removal thresholds are derived from the value of hole diameter and depth, which are 0.506 J/cm2 , 0.245 J/cm2 , 0.124 J/cm2 , 0.102 J/cm2 , 0.096 J/cm2 and 0.141 J/cm2 , 0.130 J/cm2 , 0.031 J/cm2 , 0.026 J/cm2 , 0.091 J/cm2 for diameter derivation and depth derivation, respectively, for 1, 10, 100, 500 and 1000 pulses. The deduced two sets of thresholds show similar behavior that the threshold sharply decreases with the pulse number and levels out as the pulse number exceeds 100. The phenomenon is due to incubation effects of multi-pulse irradiation on the surface of superalloy and the incubation coefficient for the thresholds calculated by diameter and depth is fitted to be ~0.72 and ~0.77.
In this study, silicon carbide ceramic (SiC) was processed by a high repetition frequency femtosecond laser with a wavelength of 1030 nm. We have analyzed the affection of different parameters to the material removal rate and researched surface oxidation phenomenon during laser scanning. The surface oxidation phenomenon is a major factor that affects the material removal rate of SiC ceramic and may even lead to failure of material removal. The oxidation phenomenon of the processing area is directly related to the laser induced temperature rise. Increasing laser scanning speed and increasing laser scanning interval are effective methods to reduce the oxidation phenomenon. The experiments have demonstrated that high-speed processing of SiC ceramic by high repetition frequency femtosecond laser is available under certain parameters.
With the rapid development of lithography technology, the processing width of lithography line is up to 10 nm. The tiny defects on the surface of substrate and particles attached to the surface have a great influence on the quality of lithography, especially the surface plasmons lithography, which requires the gap between the substrate and the mask should be controlled within dozens of nanometers, since the surface defects and particles seriously affect the quality of the surface plasmons lithography. Substrate detection device in foreign countries is costly, and the results detected by optical microscopes and electron microscopes can’t meet the requirements of the current experiment. Therefore, a set of scattering detection device needs to be developed in order to meet the requirement of the defect detection of the substrate surface.
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