  Using the space-time duality we theoretically and experimentally revisit the
Arago spot formation in the time domain and explore the temporal emergence of a
bright spot in the time shadow of an initial waveform. We describe the linear
regime of propagation using Fresnel's integrals and show that in the presence
of Kerr nonlinearity the Arago spot formation is affected depending on the sign
of the dispersion. We finally confirm experimentally the Arago spot formation
in the time domain using a telecommunication optical fiber platform.
