Multi-Wavelength Intensity-Based Interferometry for Flexible Head/Medium Interfaces

An intensity-based interferometer has been developed for measuring the steady-stale separation at the flexible head/medium interface using multiple wavelength interferometry. The approach differs from previous methods in that it employs a calibration technique that does not require a mechanical load/unload procedure nor a numerical fit of the calibration envelopes. In addition, the calibration technique improves upon previous methods in its ease of use, making the measurements both more repeatable and more accurate. The measurement range of the multi-wavelength interferometer is on the order of 25-125 nm which covers the minimal head/medium separation of magnetic storage devices currently of interest. For illustration, spacing measurements at the Bernoulli head/flexible disk interface and a linear head/tape interface using the present method have been obtained and compared with previously reported monochromatic light interferometry measurements. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in Lahaina, Hawaii, October 16-20, 1994