Defect formation in glass welding by means of ultra short laser pulses

Laser-based sample preparation for high-resolution X-ray-computed tomography of glasses and glass ceramics

X-ray-computed tomography with sub-micron resolution (nano-CT) is one of the most useful techniques to examine the 3D microstructure of materials down to voxel sizes 10 nm. However, since size and shape of samples have considerable influence on acquisition time and data quality, adapted and universally applicable workflows are needed. Three novel workflows for sample preparation using ultra-short pulsed lasers are presented which allow for reproducible fabrication, safe extraction and mounting of samples. Their application potential is illustrated via nano-CT measurements of glass ceramics as well as a laser-modified glass. Since the according sample geometries take also the requirements of other analytical techniques such as transmission electron microscopy into account, samples prepared according to the new workflows can be furthermore seen as a starting point for correlative microstructural analyses involving multiple techniques.

Process regimes during welding of glass by femtosecond laser pulse bursts

Various process regimes were observed during microwelding of glass with bursts of ultrashort laser pulses. Two major welding regimes and various subregimes were identified for two different materials. The radiation emitted by the laser-induced plasma was used to monitor different regimes that characterize glass microwelding. A comprehensive understanding of the various process regimes can be exploited to use the regimes according to their specific advantages, especially for industrial applications.

Picosecond laser welding of glasses with a large gap by a rapid oscillating scan

A welding method that utilizes a picosecond laser with a small-scale rapid oscillating scan is presented in this Letter to achieve the welding of glasses with natural stacking contact (gap≈10  μm). The rapid oscillating scan of the laser not only creates enough molten material to fill the gap, but also releases the internal thermal pressure during the welding process. The contraction created by condensation of the welding area can reduce the gap to less than 3 μm, which provides necessary conditions for realizing continuous welding. By using this method, a maximum joint strength up to 64 MPa can be achieved without any defects. The detail mechanism of laser welding with a rapid oscillating scan was revealed in this Letter. This research lays a good foundation for the laser welding of large-gap glass in practical engineering applications.