title: Measurement of the relative optical phase between amorphous and crystalline regions of the phase-change media of optical recording.
abstract: We describe a method of measuring the relative optical phase on reflection between amorphous and crystalline regions of the phase-change media of optical data storage. With a red He-Ne laser (wavelength, 632.8 nm) the relative phases on two quadrilayer optical disk stacks were measured and found to be ~40 degrees . The results are in good agreement with the calculated values based on the known layer thicknesses and refractive indices of the stacks. For calibration purposes the height of a known step on an otherwise flat silicon substrate was measured with the same apparatus. The proposed method is fairly simple to set up, can measure both front-surface and through-substrate types of optical disk, and can be used with any laser that has long coherence length.
authors.forename: R
authors.initials: R
authors.lastname: Liang
authors.forename: J K
authors.initials: JK
authors.lastname: Erwin
authors.forename: M
authors.initials: M
authors.lastname: Mansuripur