Experimental investigation of the linear polarization state of high power fusion cutting with 1 μm laser radiation

Abstract

An increase of the cut quality or enhanced process efficiency is still an aim for cutting of thick metal plates with 1.07 μm laser radiation. Nowadays, linear polarization is well investigated for CO2-lasers as an approach to a solution. The same attempt is not explored as much for laser beamfusion cutting of thick metal plates with high power solid state lasers. For this case, the present letter examines the linear polarization in contrast to statistically polarized cuts

Opportunities in laser cutting with direct diode laser configurations

“…2, the absorbed energy at the first incidence can easily range from less than 10 to as much as 90% depending on the local conditions. It has been demonstrated that the cutting performance may be considerably improved in the polarization direction, both for 10 mm [9] and 1 mm [10] wavelength radiations. Geometrically favorable states of polarization, as the ones obtained with sectioned waveplates, may generate even better absorption in the cutting kerf, as demonstrated for radial [11] and stripped [12] polarization strategies.…”

“…2, but require a defined polarization state to start from. While this is typically the output of CO 2 resonators, the process of obtaining a defined polarization state for high power fiber lasers is inefficient (>50% loss) [10]. On the contrary, a FB-DDL concept offers the unique opportunity of achieving this polarization state by avoiding polarization coupling in the power scaling step.…”

Theoretical and experimental aspects of laser cutting with elliptically polarized laser beams

“…Nevertheless, research on how to obtain radially polarized fiber lasers, through extra-cavity optical systems, was reported by Weber, Michalowski et al (2011). More recently Goppold, Pinder et al (2016) experimentally investigated cutting with a 2 kW linearly polarized fiber laser, obtained from an originally 4 kW randomly polarized laser, and demonstrated that even for relatively thick sections (8 mm) the cut performance is good, in contrast to what was expected from previous research with CO2 lasers (Niziev and Nesterov 1999). While fiber and disk lasers recently made their way into laser cutting applications, Direct Diode Lasers (DDL's) seem to be the next generation to follow.…”