Light scattering from an atomic array trapped near a one-dimensional nanoscale waveguide: A microscopic approach

Abstract

The coupling of atomic arrays and one-dimensional subwavelength waveguides gives rise to interesting photon transport properties, such as recent experimental demonstrations of large Bragg reflection and paves the way for a variety of potential applications in the field of quantum non-linear optics. Here, we present a theoretical analysis for the process of single-photon scattering in this configuration using a full microscopic approach. Based on this formalism, we analyze the spectral dependencies for different scattering channels from either ordered or disordered arrays. The developed approach is entirely applicable for a single-photon scattering from a quasi-one-dimensional array of multilevel atoms with degenerate ground state energy structure. Our approach provides an important framework for including not only Rayleigh but also Raman channels in the microscopic description of the cooperative scattering process.

Single collective excitation of an atomic array trapped along a waveguide: a study of cooperative emission for different atomic chain configurations

“…For a separation between the atoms given by a multiple of a half-wavelength of the guided mode -the well-known atomic Bragg mirror case -the system is open from both sides and exhibits a cooperative exponential decay, with a rate given by Γ C ≃ N C γ 1D /2. The scaling rate γ 1D coincides with the evaluation of the single particle selfenergy part in [22]. Let us note that the 1/2 factor results here from the polarization sensitivity of the cooperative emission on the σ − transition, see Fig.…”

“…The atoms are separated from the surface by half the fiber radius a/2 ∼ 100 nm. This configuration leads to a single-atom coupling ratio of β = γ 1D /γ ∼ 0.1, where γ 1D and γ are the radiative decay rates into the guided mode and in free space (undisturbed), respectively [13,21,22].…”

“…We considered here only the transformation of pure states, but the derivation can be straightforwardly generalized towards transformation of an arbitrary initial mixed state ρ(0). The evolution operator U (t, 0) can be found in previous work [20,[22][23][24][25] and is summarized in Appendix A.…”

Extremely subradiant states in a periodic one-dimensional atomic array

“…Such system is a versatile platform for achieving efficient lightatom coupling due to the collective nature of atomic interaction with the evanescent field of the guided mode [36]. The strong coupling of an atomic ensemble with such a nanophotonic waveguide provides opportunities to further develop the emerging field of waveguide-QED [11,37,38], in which many remarkable results were recently demonstrated not only in the field of theoretical research [38,[40][41][42][43][44][45][46][47][48][49][50][51] but also in experiments [52][53][54][55][56][57][58], including observation of subradiant states [59].…”

Waveguide quantum electrodynamics: collective radiance and photon-photon correlations

“…(Kornovan et al, 2016) and in a similar approach in Ref. (Pivovarov et al, 2018). At the lowest nonvanishing order, the matrix element of the level-shift operator can be written as:…”