Track/Focus control of cantilever type near field optical head for high density and fast data transfer rate data storage device

摘要

A self-sensing cantilever is attached on the commercial optical disk drive system to verify feasibility of tracking and focusing optical recording head with a sub-wavelength aperture cantilever tip for the high areal density data recording and reading. In tracking control, a VCM head is controlled multi-offset by dividing photodiode signal into 16 levels. In focusing control, based on the frequency separation scheme, we controlled the VCM head to follow the low frequency surface profile and measured the gap between tip and sample at high modulation frequency, simultaneously.