Observation of Self-Trapping of Light in a Self-Written Channel in a Photosensitive Glass

We report the observation of self-trapping of light in a self-written channel in a photosensitive glass waveguide. As the refractive index changes induced in the glass are permanent, the resulting channel is also permanent. We show that the evolution of this structure agrees well with theoretical predictions. This will allow us to confirm experimentally predicted phenomena such as beam interaction and self-similar evolution of the refractive index and the intensity.