Observation of fundamental dark spatial solitons in semiconductors using picosecond pulses

We report what is to our knowledge the first observation of fundamental dark spatial solitons. The solitons are launched in bulk semiconductors using an initial condition with odd symmetry. In order to form the initial condition, a glass platelet is positioned in one half of an incident 30-psec pulse, creating a pi phase shift in the spatial profile. Several propagation parameters for the solitons are measured experimentally, and good agreement with theory is obtained.