Acoustic emission of laser textured disks influenced by bump excitation

The acoustic emission behavior of laser textured disks was studied in both time and frequency domains. The high intensity peaks observed during a starting process are related to specific rotational speeds. Some peaks are associated with slider body resonance excited by a harmonic of the laser bump interaction. A finite element analysis was performed to determine the natural frequencies of sliders. The AE intensity curve can give a correct take-off velocity for a laser textured disk if at least one harmonic component of the bump excitation falls within the filter range at the real take-off velocity. With amplifier settings similar to those for mechanically textured disks, it is not feasible for an AE system to detect contact if the bump spacing is smaller than a critical value