Facilitated glass separation by asymmetric Bessel-like beams

Abstract

The modification of transparent materials is enabled by focused ultrashort laser pulses. Single pass processing up to several millimeters can be achieved by the usage of elongated beam profiles. We studied the mechanical separability in dependence of the material thickness. As simulations show, asymmetric beam profiles can cause modifications with preferential direction reducing the necessary breaking force. Pump-probe microscopy is implemented to examine the laser-matter-interaction. We present a measured 3D-reconstruction of the transient interaction inside the material and elucidate the desired crack formation. We demonstrate beam shaping concepts to create a new, efficient and robust class of Bessel-like beams, which can be used to achieve a preferred crack direction. We verify the concept by modification and separation of silicate glasses.

Ultrafast thin-disk multi-pass amplifier system providing 1.9 kW of average output power and pulse energies in the 10 mJ range at 1 ps of pulse duration for glass-cleaving applications

“…Subsequent experiments will aim at industrial processes like laser-based cleaving of thick glass specimens used in safety and architectural applications. After acceptance, Jenne et al [38] discussed an optimized orientation of stress distribution inside the material by usage of asymmetric beam profiles, which should be a promising approach to facilitate cleaving of very thick glass by elongated modifications induced by multi-kW high energy ultrafast lasers as presented in this work.…”

Structured light for ultrafast laser micro- and nanoprocessing

“…6,23 Figure 2 provides a menu of nondiffracting beams tailored for various processing strategies. 6,7,46 First reports on Bessel-like beam generation were based on ring-slit apertures (far-field generation). 52 However, for efficiency reasons, the axicon-based generation (near-field) 39 is preferred.…”

“…6,42 We use a generalization of this concept to generate nondiffracting beams with arbitrary transverse intensity profiles. 7,41 Now, the generalized axicon-like phase transmission T gen ¼ expðιΦ gen Þ is characterized by a phase modulation with arbitrary azimuthal dependencies ΘðϕÞ and, thus E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 0 0 1 ; 1 1 6 ; 1 3 4 Φ gen ðr; ϕÞ ¼ k r r þ ΘðϕÞ:…”

“…More sophisticated spatial distributions become especially attractive when considering efficient, industry-compatible concepts intended to yield high throughputs. [5][6][7][8] Thus, in addition to the remarkable temporal properties of ultrashort pulsed lasers, there is a need for tailored focus distributions in all spatial degrees of freedom. 6,9,10 Recently, the term "structured light" has been used to cover advanced beam shaping concepts in which all spatial and temporal properties of laser radiation are manipulated to achieve tailored light states.…”

“…The broad accessibility of liquid-crystal-based spatial light modulators (SLMs) has attracted the attention of the laser processing community, too. 6,7,[22][23][24][25] There is ongoing progress regarding the display's ability to resist high peak and average powers, so that these devices may be part of future industrial processing optics forming ultrashort pulsed optical radiation in the kilowatt and tens-of-millijoules class. [26][27][28] Equally conceivable are concepts where the laser system itself is able to provide structured light.…”