Optical Reading From Videotapes Using Magnetic Garnet Film

In order to greatly increase the speed at which videotapes are read, we propose an optical reading method using a magnetic garnet film. This method allows several data tracks to be read in parallel. In order to realize the optical reading of data, the magnetic garnet films need to have not only high...

Full description

Saved in:
Bibliographic Details
Published in:IEEE transactions on magnetics 2008-11, Vol.44 (11), p.3289-3292
Main Authors: Kishida, M., Hayashi, N., Iwasaki, K., Umezawa, H., Nomura, T.
Format: Article
Language:English
Subjects:
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
Faraday effect
Film thickness
Frequency ranges
Garnet films
Garnets
Laboratories
Lasers
Magnetic films
Magnetic flux
Magnetic recording
magnetic tapes
Magnetism
Materials science
Micrometers
Microscopes
Noise levels
Optical films
Optical recording
Other topics in materials science
Physics
Research and development
Rotation measurement
Videotape
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In order to greatly increase the speed at which videotapes are read, we propose an optical reading method using a magnetic garnet film. This method allows several data tracks to be read in parallel. In order to realize the optical reading of data, the magnetic garnet films need to have not only high enough resolution for all data to be transferred from the videotape, but also a large Faraday coefficient for data to be reproduced with a high carrier-to-noise ratio (CNR). We have constructed trial films with a Faraday rotation angle of approximately 5 deg per micrometer film thickness when a green laser is used. The data patterns transferred from a D-3 format videotape were clearly observed using a polarizing microscope. An experiment to reproduce videotape data was carried out at a tape speed of 0.367 m/s, and a CNR of over 30 dB was achieved for a bit-length of 0.385 mum. The film had a constant real permeability over a frequency range of 40 MHz, which corresponds to a tape speed of 353x with respect to the D-3 system.
ISSN:0018-9464
1941-0069
DOI:10.1109/TMAG.2008.2001623