  We measure the superradiant emission in a one-dimensional (1D) superradiance
lattice (SL) in ultracold atoms. Resonantly excited to a superradiant state,
the atoms are further coupled to other collectively excited states, which form
a 1D SL. The directional emission of one of the superradiant excited states in
the 1D SL is measured. The emission spectra depend on the band structure, which
can be controlled by the frequency and intensity of the coupling laser fields.
This work provides a platform for investigating the collective Lamb shift of
resonantly excited superradiant states in Bose-Einstein condensates and paves
the way for realizing higher dimensional superradiance lattices.

Quantum Gases