A computer memory system is disclosed which includes a randomly and electrically accessible semiconductor "page"memory. The semiconductor page memory is conventional to the extent that it includes a planar array of electrically-accessible flip-flops for storing a corresponding number of binary information bits. In addition, each flip-flop is provided with a photosensor by which the flip-flop can be set in response to received light, and is provided with a light valve controlled by the state of the flip-flop. A laser light source, a light deflector and holographic optics are provided to create a hologram of the array of light valves at any one of many small areas on an erasable holographic storage medium. Subsequently, the hologram can be illuminated to recreate and project the image of the array of light valves onto the array of photosensors to return the information to the flip-flops in the semiconductor page memory. In this way, the semiconductor page memory serves as a page-at-a-time electrical input-output unit for a great many pages of information stored optically on the erasable holographic storage medium.
A holographic system for storing data on an interference pattern in a hologram storage medium includes a light source for emitting a laser beam, a beam splitter, modulating means and a refractive material. The beam splitter divides the laser beam into a reference beam and a signal beam and the modulating means modulates the signal beam to generate a modulated signal beam. The refractive material refracts the reference beam to generate a refracted reference beam, wherein the refracted reference beam interferes with the modulated signal beam in the hologram storage medium to generate the interference pattern.
An optical pickup including a stem; a substrate mounted on the stem; a laser diode mounted on, and electrically insulated from, the substrate; and a photodetector provided on the substrate for detecting return light from an object to be irradiated. The substrate is biased at a given voltage and has an insulating member opposed to the stem. The laser diode has a first electrode opposed to the substrate with a first insulating film, a conductor film, and a second insulating film interposed between the first electrode and the substrate.
