Abstract
Direct visualization method for molecularly thin lubricant films on magnetic disks is presented. Visualization of a molecularly thin film is an extremely useful technique for the investigation of replenishment and retention of thin lubricant films. Ellipsometry can provide thickness and refractive index of a molecularly thin film. However, conventional ellipsometry requires the laser spot to be scanned in order to image a lubricant film, since it can provide information of only one point of a sample surface. In this report, direct visualization method based on ellipsometry is presented. In our elllipsometric microscope, ellipsometric information of a sample surface is converted into dark-bright contrast and is directly visualized with a chilled CCD camera. By the combination of optical and digital image processing techniques, weak contrast are enhanced and interference noise caused by laser coherence are reduced. Thus, our method can provide direct visualization of 1-nm order thick thin lubricant film.
