Low-temperature storage using GaAs lasers and EuO as storage medium

Abstract

The feasibility of a beam-addressable memory using EuO as a storage medium and GaAs laser as a transducer has been discussed in a previous paper. In this paper we shall present the results of a series of high-speed, dynamic read/write experiments and discuss the system implications of these experiments. A mechanical scanner was constructed to carry out the dynamic read/write experiment and a refrigeration system was used to provide both the cooling of the GaAs laser and the storage medium. Writing was accomplished by pulsing the laser as the light spot scanned across the film surface. The energy density required to write a 5 μ spot is below 10-2 erg. This is within the capability of GaAs lasers, hence writing time in tens of nanoseconds was easily achieved. Reading is achieved by scanning a cw GaAs laser beam across the film surface and detecting the magneto-optic signal through a cross polarizer by a PMT. Due to the large magneto-optic effect, very high-speed readout is achieved. The high-speed read/write experiment showed the feasibility of a reversible storage system which has the density and speed of an optical store. A brief comparison of this technology with that of the gas laser is given. © 1970 The American Institute of Physics.