Bragg condition for scattering into a guided optical mode

TL;DR

This paper presents a theoretical study of light scattering into guided modes of a waveguide from an atomic array, revealing a modified Bragg condition and diverse scattering behaviors influenced by atom-light interactions.

Contribution

The work introduces a modified Bragg condition for scattering into waveguide modes, accounting for dispersive interactions and revealing new parameter regimes for scattering behavior.

Findings

Scattering is enhanced at angles deviating from the geometric Bragg angle.

Different regimes show linear, quadratic, oscillatory, or constant dependence on atom number.

Results are robust against imperfections in the atomic array.

Abstract

We theoretically investigate light scattering from an array of atoms into the guided modes of a waveguide. We show that the scattering of a plane wave laser field into the waveguide modes is dramatically enhanced for angles that deviate from the geometric Bragg angle. We derive a modified Bragg condition, and show that it arises from the dispersive interactions between the guided light and the atoms. Moreover, we identify various parameter regimes in which the scattering rate features a qualitatively different dependence on the atom number, such as linear, quadratic, oscillatory or constant behavior. We show that our findings are robust against voids in the atomic array, facilitating their experimental observation and potential applications. Our work sheds new light on collective light scattering and the interplay between geometry and interaction effects, with implications reaching beyond the optical domain.