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°. 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.
© 2000 Optical Society of America
(120.4530) Instrumentation, measurement, and metrology : Optical constants
(210.0210) Optical data storage : Optical data storage
(210.4590) Optical data storage : Optical disks
(210.4770) Optical data storage : Optical recording
(210.4810) Optical data storage : Optical storage-recording materials
Rongguang Liang, J. Kevin Erwin, and Masud Mansuripur, "Measurement of the relative optical phase between amorphous and crystalline regions of the phase-change media of optical recording," Appl. Opt. 39, 2167-2173 (2000)