Figure 4
Surface topography maps after laser machining: The surface topography maps observing a single trench machined by (a) the picosecond laser at a feed speed of 4.0Â mm/s, (b) The picosecond laser at a feed speed of 1.0Â mm/s where cracks that are propagating perpendicular to the feed direction from the kerf edges are visible, (c) The nanosecond laser at a feed speed of 6.0Â mm/s, (d) The continuous wave laser at a speed of 35.0Â mm/s