US 12,749,505 B1 · Magneto-optical Kerr effect reader for hard disk drives

Abstract

Described are disk drives that utilize the magneto-optic Kerr effect (MOKE) in near field to read data that has been recorded on magnetic media. When polarized light is reflected from the surface of magnetic media at a perpendicularly magnetized bit, polar MOKE results in rotation of the polarization of the light. A reader configured to analyze the polarization orientation of light reflected from recorded bits can be used to discern the states of the bits. Near-field transducers such as used in some heat-assisted magnetic recording disk drives may be used to emit polarized light that is incident on the surface of the recording medium.

Claims20

Dependent claims

A disk drive comprising:

an optical reader configured to detect states of magnetically recorded bits from a magnetic medium, the optical reader comprising:
a light source configured to emit polarized light incident on the magnetic medium at a location of incidence to produce reflected light, the reflected light having a polarization state that is rotated based on a magnetization state of the magnetic medium at the location of incidence;
and
a detector configured to receive the reflected light and to detect intensity of a selected polarization state of the reflected light to thereby determine the magnetization state of the magnetic medium at the location of incidence, wherein the detector comprises a polarization analyzer configured to filter the reflected light based on polarization state.

1 more element

Dependencies are inferred from the claim text.

Magneto-optical Kerr effect reader for hard disk drives

Life of this patent

Magneto-optical Kerr effect reader for hard disk drives

Life of this patent

Abstract

Claims20