Normal incidence polarization interferometer for measuring flying height of magnetic heads

In this paper, we give a brief review and analysis to the two currently most powerful methods for flying height testing of magnetic heads-intensity interferometry and polarization interferometry. Then a dual-beam normal incidence polarization interferometry method is proposed to compromise the disadvantages of the above two methods. The proposed method not only has the advantages of both the above methods, but also can be used to measure the pitch and roll of the head-slider dynamically. Design details and analysis of the relationship between the optical parameters of the tester and its testing accuracy are given