Fig. 1. Schematic diagram of head model

Fig. 2. Relationship of light intensity on detector I and film thickness h

Fig. 3. Relationship of light intensity on detector I and film thickness h with different polarizing angles

Fig. 4. Schematic of VEM structure

Fig. 5. Schematic diagram of light converging on back focal plane of objective lens

Fig. 6. Simulated relationship between contrast ratio Ce and incident angle θ when film thickness h=1 nm

Fig. 7. Microscopic images for different pinhole diameters. (a) 20 μm; (b) 50 μm; (c) 100 μm; (d) 1 mm

Fig. 8. Schematic of light source

Fig. 9. Resolution test result of USAF1951 resolving power test target pattern taken by VEM

Fig. 10. Knife-edge image taken by VEM. (a) Knife-edge parallel to the incident plane; (b) knife-edge perpendicular to the incident plane

Fig. 11. Resolution of VEM obtainedby knife-edge imaging. (a), (b), (c) are the ESF, LSF and MTF curves in the horizontal direction, respectively; (d), (e), (f) are the ESF, LSF and MTF curves in the vertical direction, respectively

Fig. 12. Relationship between the normalized reflected light intensity and film thickness of nonpolar lubricant film

Fig. 13. Dewetting images of lubricant film on the head obtained at different shooting times after film coating. (a) 5 min 30 s; (b) 5 min 50 s; (c) 6 min 10 s; (d) 6 min 30 s

Fig. 14. Magni?ed images of the head lubricant dewetting phenomenon in the upper left rectangle area of Fig. 13 obtained at different shooting times after film coating. (a) 5 min 30 s; (b) 5 min 50 s; (c) 6 min 10 s; (d) 6 min 30 s

Fig. 15. Cross-sectional view at central line L in Fig. 14