Simple digital system for the stabilization of holographic recordings of a slow grating in photorefractive materials

We report on a digital system for the stabilization of an interference pattern of light fringes. This system uses a Raspberry Pi computer to operate a continuously stabilized setup and, because of the particular features of this stabilization setup, it is possible to record slow gratings in photorefractive materials. Our system proved to be effective, less expensive, and easy to operate, compared to the frequently employed setup with a lock-in amplifier, as it does not require specific equipment and/or specialized personnel.