Figure 6
From: Focus Tracking System for Femtosecond Laser Machining using Low Coherence Interferometry
(a) Optical scattering profile as function of time or FLP (4 kHz rep. rate) for a dual layered metal sample. As machining starts (t0) the system identifies the sample surface and bronze is rapidly etched. The laser, then, reaches the steel layer (t1). The system keeps track of the crater evolution (t2 and t3). (b) An illustration of the process.
