Dynamic response of a Winchester-type slider measured by laser Doppler interferometry

Optical interferometric techniques have been used extensively in the past to measure the time-averaged flying height of self-acting, gas-lubricated slider bearings commonly found in magnetic recording disk files. Recently, their application has been extended to dynamical measurements[1,2]. Previously used optical techniques have an inherent disadvantage in that they require a specially made glass disk, which is different from the usual oxide coated aluminum disks. Also, they are applicable only to steady state measurements. This paper presents a laser Doppler technique capable of measuring the dynamic response of a slider in an unmodified magnetic disk file.