Abstract: A writing, erasing and readout system for a magneto-optic recording medium capable of achieving switching rates approaching the laser pulse rate, including plural diode lasers operating through a single optical path and cooperating with bi-polar magnetic field producing means located adjacent to and on the opposite side of the magneto-optic medium.

Abstract: An improved collimating and conversion means is provided in a single system component that can be easily formed in a cost effective manner to convert an elliptically shaped collimated beam into a circular beam. The single component of this invention is a semiconductor laser beam collimator comprising means for collimating an output beam of radiation emitted from a semiconductor laser having a substantially elliptical cross sectional configuration and converting the emitted beam of radiation into a beam of circular cross sectional configuration, the means characterized by consisting of a graded-index (GRIN) rod or fiber with one end of the rod being beveled at an angle. The length of the GRIN rod bevel and the bevel angle are chosen according to the particular diameter and optical power of the emitted beam of the semiconductor laser.

Abstract: Magneto-optic media and system optimization including a set of optimized magneto-optic media for use in a magneto-optic recording and readout system employing an incident readout light beam of a given fixed power, P.sub.o. The beam is delivered in a linearly polarized state to the magneto-optic media and the magneto-optic radiation received from the media is detectable by the system. Each member of the set of media comprises a reflective layer having a predetermined thickness, a first transparent layer overlying the reflecting layer and having a predetermined thickness and refractive index and a second light transmissive layer having a predetermined thickness and exhibiting absorptivity at the wavelength of said incident readout light beam and having magneto-optic conversivity and perpendicular anisotropy. Members of the set of optimized magneto-optic media may further included a third transparent layer overlaying the second transmissive layer and having a predetermined thickness and refractive index.

Abstract: Deposition of continuous pin-hole free tellurium films with thicknesses to less than 150A on a suitable substrate is achieved by first pretreating the substrate prior to film deposition. Ion sputtering or bombardment of the substrate surface with an inert gas prior to tellurium evaporation creates a dense coverage of nucleation sites on the substrate which improves the adhesiveness and resistance to abrasion and oxidation of the deposited film while providing very thin pinhole free films of uniform thickness and desired crystallite orientation.

Abstract: A multilayered reflector structure deposited on the light emitting surface of a semiconductor electroluminescent device and consecutively comprising a layer of low refractive index material, a layer of intermediate refractive index material and a layer of high refractive index material. Ablative means remove and form an aperture in the outer high index layer at the region of optical radiation emission from said device whereby the level of reflectivity is highest at the center of the aperture as compared to structure regions adjacent to the aperture. In this manner, fundamental mode stabilization may be achieved. Also disclosed is a nonablated three layered reflector structure.