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Magneto-optic Medium With Equatorial Kerr Effect Enhanced by Surface Plasmon Effect

IP.com Disclosure Number: IPCOM000041137D
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Jurich, M: AUTHOR [+2]

Abstract

The equatorial or transverse Kerr effect causes the reflection of a wave to depend linearly on the magnetic field. This effect can be used to read a magneto-optic memory without resolving the reflected polarization. The effect is normally small, but is enhanced when the wave-vectors of the beam in the magnetic medium become nearly parallel to that of the reflected wave. Such a situation is common when a surface plasmon has been excited at the interface of a low-loss metal film (e.g. silver) with a low index medium such as air. At a surface plasmon resonance, the reflectivity of the film drops and becomes increasingly sensitive to loss.

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Magneto-optic Medium With Equatorial Kerr Effect Enhanced by Surface Plasmon Effect

The equatorial or transverse Kerr effect causes the reflection of a wave to depend linearly on the magnetic field. This effect can be used to read a magneto-optic memory without resolving the reflected polarization. The effect is normally small, but is enhanced when the wave-vectors of the beam in the magnetic medium become nearly parallel to that of the reflected wave. Such a situation is common when a surface plasmon has been excited at the interface of a low-loss metal film (e.g. silver) with a low index medium such as air. At a surface plasmon resonance, the reflectivity of the film drops and becomes increasingly sensitive to loss.

A Magneto-Optical (M-O) film is deposited along with a plasmon film in such a way that the plasmon resonance becomes sensitive to the magnetically modulated loss in the M-O medium. When the M-O medium is deposited at the silver-air (or low index) interface, its loss dominates that of the silver. Small changes in M-O medium loss modulate the plasmon resonance, which has, however, been broadened and shifted. When the M-O medium is deposited at the silver-glass (or high index) interface, it perturbs the plasmon relatively little. The resonance becomes narrow and deep, but continues to have higher sensitivity to equatorial Kerr effects than bulk film.

Such a medium can be used to store information. The substrate has a high refractive index and is groove...