# Two-photon pulse scattering spectroscopy for arrays of two-level atoms, coupled to the waveguide

## TL;DR

This paper presents a theoretical analysis of two-photon pulse scattering from an array of two-level atoms coupled to a waveguide, deriving analytical expressions and exploring photon storage times related to array periodicity.

## Contribution

It provides a new analytical framework for understanding two-photon scattering and photon storage in atom arrays coupled to waveguides, highlighting the role of array period.

## Key findings

- Maximum photon storage times occur at anti-Bragg periods, specifically at quarter-wavelength structures.
- Derived a general analytical expression for scattered two-photon pulses.
- Analyzed contributions of various eigenstates to the scattering process.

## Abstract

We have theoretically studied the scattering of 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 have also calculated the dependence of the time incident photons are stored in the array on its 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 $\lambda/4$.