Dark photorefractive spatial solitons and photorefractive vortex solitons.

We report on the first experimental observations of dark, planar, spatial photorefractive solitons, and photorefractive vortex solitons that are trapped in a bulk (three-dimensional) photorefractive media. Both the dark and vortex solitons possess the ``signatures'' of the photorefractive solitons: they are independent of absolute intensity, can afford significant absorption, and are inherently asymmetric with respect to the transverse dimensions of trapping.