Self-organization of laser cavities using dynamic holograms

Inserting a photorefractive crystal inside a laser cavity leads to striking behaviors. The oscillating modes record a dynamic hologram in the crystal, which in turn acts as a spectral filter for these modes. For a correctly designed system, this mutual adaptation spontaneously forces the laser to oscillate on a single longitudinal mode. We describe this self-adaptive process, and we illustrate its operation in the case of two different lasers.