Two-photon pulse-scattering spectroscopy for arrays of two-level atoms coupled to a waveguide

We theoretically studied the scattering of short two-photon pulses from a spatially separated array of two-level atoms coupled to the waveguide. A general analytical expression for the scattered pulse has been obtained. The contributions of various single-eigenstate and double-excited eigenstates of the array have been analyzed. We also calculated how the time, during which the incident photons are stored in the array, depends on the array period and the number of atoms. The largest storage times correspond to the structures with the anti-Bragg period, equal to the quarter of the wavelength of light at the atom resonance frequency λ/4.