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Proceedings Paper

Photodichroic Silicate Glass Surface
Author(s): Chie-Kuang Wu
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Paper Abstract

The photodichroic silicate glass surface is a direct-read-after-write laser recording material which permits instant optical recording without processing of any kind. The required writing energy density at wega Hz rate and higher is 40 mj/cm2. An even, better writing sensitivity is expected for a preconditioned glass surface which is yet to be demonstrated at mega Hz rates. The inherent resolution. capability of this material is better than 2000 cycles/mm, which is consistent with the fine grain structure of the photodichroic silicate glass surface (grain size <0.02μm). The photodichroic silicate glass surface can be pre-recorded. with tracks of width fpm or less. It is potentially a pin-hole-free recording material due to the inherent homogeneity of the silicate glasses, and to the very small sizes of the photosensitive crystals, relative to the wavelength of light and the thickness of the surface layer. The physical effect of recording is irreversible, yet the recorded spots or bits are erasable. The erased 1-bit can be distinguished easily from the o-bit of course, not distinguishable in the normal read mode), when necessary. There is also a mechanism. to prevent erasing after recording and error corrections are completed. The writing is done with a polarized red light, and non-destructive read is done using a near infrared beam, with the recorded bits between crossed polarizers. The erasure is to re-expose with the wrice beam whose polarization direction has been rotated 45° with respect to the initial polarization exposure direction. In this manuscript, the physical effect of recording is discussed in detail, including the intensity dependent writing sensitivity, the threshold, effect, and the relationships among observed spot size, contrast and the writing energy iliensity. Recording in mega Hz rates as well as write-erase cycling are demonstrated. The read contrast of the recorded image is studied using video microscopy, and the transmission spectra of 1-bits between. crossed polarizers are measured. The origin. of the read contrast is discussed, and the experimental data on the spectra of dichroic absorption difference together with the associated birefringence are presented.

Paper Details

Date Published: 12 February 1980
PDF: 12 pages
Proc. SPIE 0200, Laser Recording and Information Handling, (12 February 1980); doi: 10.1117/12.958066
Show Author Affiliations
Chie-Kuang Wu, Corning Glass Works, Research and Development Laboratory (United States)

Published in SPIE Proceedings Vol. 0200:
Laser Recording and Information Handling
Albert A. Jamberdino, Editor(s)

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