Abstract: In a high-frequency light polarization modulating device including a source of polarized light (SL), a generator (BOBI) of a periodic magnetic field (H.sub.p) having a pulsation (.omega.) and a magnetooptical garnet (GRI) receiving the beam (F.sub.i) emitted by the source and the field (H.sub.p), in order to produce a beam (F.sub.mi) of modulated polarized light, the invention provides that the generator (BOBI) comprises a microcoil disposed on the garnet in such a manner as to produce a magnetic field perpendicular to it. The garnet (GRI) is monocrystalline, in thin layers, and anisotropic, and its direction of easy magnetization is perpendicular to its plane. The invention is applicable to magnetooptical memories.

Abstract: A device and method for writing data on a magnetic medium (SMI) are disclosed for use in connection with a recording layer (CMI1) made from an anisotropic material having the axis of easy magnetization perpendicular to its surface and which moves past at least one magnetic writing transducer (TMI). According to the invention, this device is characterized by the fact that the transducer comprises two adjoining writing poles (PEI1, PEI2) having opposite polarities and supplying simultaneously, in a direction (Oz) parallel to the surface of the layer and perpendicular to the base material's direction of motion, magnetic writing fields (Hy) which are normal to the surface of the layer with opposite polarity. The device is particularly applicable for writing data on a magnetic disc adapted for opto-electronic readout.

Abstract: A multilayer magnetic recording medium including at least one magnetic layer (CMOI) formed of an alloy including one of the group of heavy rare earths and a metal of the group of the first series of transition metals surrounded by at least two dielectric layers.According to the invention, the magnetic medium is characterized in that it includes means for preventing the diminution of the number of atoms of rare earth participating in the magnetism of the magnetic layer disposed on both sides of the magnetic layer.Applicable to magnetooptic disks.

Abstract: Optical apparatus (DISFOCI1 to DISFOCI4) for focusing a beam of light for reading of a data medium moving past it, comprising, a main body (CPLI1 to CPLI4) disposed to fly above the data medium and at least one optical device (OPFOCI1, OPFOCI2, OPFOCI3, OPFOCI4, OPFOCI5) for focusing of the beam, the optical device being located such that its distance in relation to said medium remains constant. The optical device is placed on the main body and is integral with the movement thereof. The apparatus is adpated for optical reading of magnetic optical data.

Abstract: A pattern generator for integrated multilayer circuits, comprising a light source (SLI) for each one of the layers, at least one associated reticle (RETMI) bearing patterns to be reproduced thereon and which is transparent to light, and optical means (MPI) for projecting and focusing the image of the patterns on the layer. The generator is characterized in that with a polarizer (POLI) being connected to the source, the reticle comprises a thin layer (GRI) of magnetooptical material with a magnetization which is at right angles to its surface, the image not the patterns being restituted by a light meter (ANALI).