Flyability and flying height modulation measurement of sliders with sub-10 nm flying heights

An experimental system is set up, and a procedure is proposed for measuring the flying height modulation (FHM) at the head-disk interface of a magnetic disk drive by using laser Doppler vibrometry (LDV). A precision trigger, a large number of averages, and a suitable filter are key to successfully measuring the FHM. Better results can be obtained from the velocity output of the LDV as opposed to the displacement output.