Effects of laser operating parameters on metals micromachining with ultrafast lasers

High-speed and crack-free direct-writing of microchannels on glass by an IR femtosecond laser

“…The technological modes around this curve are close to optimal if the task is to obtain microchannels with a large depth and low roughness. According to [27,35], the minimal Ra for metals is reached at the 50% overlap; for nanosecond laser machining of glass, it is in the 60-80% range [36]; for fs laser processing of Si, it was found at the 84% overlap [37]. In the selected overlap range (50-68%), we did not find any statistical dependence of Ra on the overlap; so we assume that this range is optimal, though the range of overlap values should be widened to ensure it.…”

Femtosecond laser ablation of cadmium tungstate for scintillator arrays

“…The normalised pulse overlap (NPO) is the degree of overlap for subsequent pulses as they are scanned across the sample. It can be defined by the spot diameter D, the scan speed V, the pulse duration τ p and the laser repetition rate R as follows: (D À(V/R)À V*τ p )/(D)¼NPO [11]. Hence, a higher NPO corresponds to a greater overlap of pulses.…”

Heat Accumulation in Laser-Based Removal of Space Debris

“…For ground-based LDR, rather long pulses with pulse durations typically in the range of τ L 1-50 ns are commonly proposed [3,4,8]. In contrast to ultrashort pulses, which are typically used in laser material processing, nanosecond pulses are related to a significantly larger heat-affected zone in the target material than ultrashort pulses, which are commonly associated with cold ablation [9].…”