Magneto=optical modulator using Faraday effect - depends on light modulation matrix for image representation or storage

• Main Authors: KILLAT,ULRICH,.DR, RABE,GERT
• Format: Patent
• Language: English; German
• Published: 20.03.1980
• Edition: 3
• Subjects: DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

The modulator comprises a ferromagnetic layer (2), with a high Faraday rotation, containing a number of domains (4), displayed via a perpendicular magnetic field for modulating an incident light beam. An optical polarisation element is used for polarising and analusing the light beam. The ferromagnetic layer (2) has separate islands (3) which are magnetically isolated from the ferromagnetic layer (2) and which determines the size and path of the domains (4) within the latter or within the island. Immediately adjacent the domains (4) are electrical conductor paths for providing the perpendicular magnetic fields. Pref. each conductor path comprises one coil turn (5) overlying a respective island (3), the inner dia. of which is large compared with the extent of the domains (4) within the island (3).