Flying height measurement using frustrated total reflection: determination of the reflectivities by the least-squares method

A new method for determining reflectivities in flying height measurement of a slider using frustrated total reflection (FTR) sensor is evaluated. The method is based on the fact that the reflectivity of FTR has different dependence on flying height for P-polarized light and S-polarized light. The flying height of a slider on a glass disk was measured both by an FTIP sensor using this method and by a traditional flying height tester. The results agree with each other with an error of less than 3 nm.