Industrial Excimer Laser Research Articles

Effect of tungsten doping on laser ablation and graphitization of diamond-like nanocomposite films

Laser surface microstructuring of diamond-like nanocomposite (DLN) films is a promising technique to improve their properties. For industrial applications, UV excimer or IR lasers with high pulse repetition rate are commonly used. In this paper, we investigate the influence of metal (tungsten) doping of DLN film on the ablation and graphitization behavior of the films using KrF laser (λ = 248 nm, τ = 20 ns) and Yb:Yag laser (λ = 1030 nm, τ = 8 ps). The response is found to be sensitive to the laser wavelength and pulse duration. For UV ns-pulses, the ablation threshold is insensitive to W-doping, showing only a slight increase for the highest tungsten concentration of 27 at.%, while the ablation rate decreases. Conversely, an increase of tungsten content in the case of the irradiation by IR ps-pulses induces a drop in the ablation threshold and an increase in the ablation rate. The structural modification of the films is analyzed by Raman spectroscopy, which also allows us to estimate the thickness of a residual graphitized layer on the surface after laser irradiation. It is found that laser-induced graphitization is stronger for doped DLN films after multipulse irradiation.

Powerful Industrial Excimer Configured for High Altitude Water Vapor Measurements

AbstractTo improve the sensitivity and range of atmospheric water vapor measurements by ultraviolet Raman lidar, a powerful 308 nm industrial excimer laser was modified to deliver frequency‐stabilized, narrowline output with low divergence and linear polarization.

Focus on lasers and optics

Focus on lasers and optics

Industrial excimer laser beam properties

As excimer lasers have evolved over the last two decades, their beam properties and characteristics have become better understood by advanced diagnostic techniques. This understanding is crucial for two reasons. First, in large volume industrial processes yield is proportional to laser beam consistency and is a crucial factor in determining whether or not a process is economically viable. The second area is in understanding the ablation phenomenon. Usually, it is assumed during research or process development that a laser pulse is a laser pulse when, in actuality, the pulse characteristics vary. This paper presents methods which can be used to improve the characterization of KrF excimer laser pulses in hopes of furthering cooperation between laser manufacturers, system integrators, and users.

Degradation of Transmission of Silica Glass on Excimer Laser Irradiation

The effects of prolonged irradiation of KrF (248nm) and ArF (193nm) lasers on the optical properties of silica glass were studied, with a glass made from a high purity silicon tetrachloride by the oxy-hydrogen flame hydrolysis method for sample. Experiments were conducted as an acceleration test for services in excimer laser apparatuses, and the results were examined in terms of solarization, i.e., degradation in transmission, T, or increase in the absorption coefficient at 5.8eV, k2, as a function of the per pulse laser energy density, e. It was found that k2 was related to e as in: for KrF excimer laser: k2=2.38×10-7⋅e3.15(e⋅p)1.31, and for ArF excimer laser: k2=8.71×10-8⋅e1.42(e⋅p)1.45, where p is the number of shots. It was demonstrated that these formulas were precise enough to make reasonable estimates of the service lifetime for silica glass in industrial excimer laser apparatus, where the intensity of the laser would be much smaller.