Spontaneous emission and energy shifts of a Rydberg rubidium atom close to an optical nanofiber

Abstract

In this paper, we report on numerical calculations of the spontaneous emission rates and Lamb shifts of a 87 Rb atom in a Rydberg-excited state (n 30) located close to a silica optical nanofiber. We investigate how these quantities depend on the fiber's radius, the distance of the atom to the fiber, the direction of the atomic angular momentum polarization, as well as the different atomic quantum numbers. We also study the contribution of quadrupolar transitions, which may be substantial for highly polarizable Rydberg states. Our calculations are performed in the macroscopic quantum electrodynamics formalism, based on the dyadic Green's function method. This allows us to take dispersive and absorptive characteristics of silica into account; this is of major importance since Rydberg atoms emit along many different transitions whose frequencies cover a wide range of the electromagnetic spectrum. Our work is an important initial step toward building a Rydberg atom-nanofiber interface for quantum optics and quantum information purposes.

Repulsive Casimir-Polder potentials of low-lying excited states of a multilevel alkali-metal atom near an optical nanofiber

“…We take into account the contributions of electric dipole transitions but neglect the contributions of electric quadrupole transitions. We note that this approximation is valid when the atom is not highly excited and the atom-to-body distance is not too small [38].…”

“…Such effects have been studied for a large number of systems [30,31]. In the particular case of an atom near a nanofiber, the modifications of the radiative decay have been investigated in the context of a two-level atom [32][33][34] as well as a realistic multilevel alkali-metal atom [19,[35][36][37][38]. The shift in the energy level of the atom caused by the presence of the body depends on the position of the atom and is known as the Casimir-Polder potential.…”

“…Recently, the Casimir-Polder potential of a rubidium atom in a Rydberg state near a nanofiber has been calculated [38] using the nonretardation approximation [45]. In the numerical calculations of Ref.…”

“…In the numerical calculations of Ref. [38], the multilevel structure of atomic rubidium has been accounted for by summing up the contributions of the individual transitions between a large number of magnetic sublevels. Several related works have been reported [46][47][48][49][50].…”

The Quantum Optics of Asymmetric Mirrors With Coherent Light Absorption

“…For example, inside a homogeneous dielectric medium with refractive index n, the spontaneous decay rate Γ med of an atomic dipole equals (Glauber and Lewenstein, 1991;Scheel et al, 1999) Γ med nΓ air (1) to a very good approximation, where Γ air denotes the corresponding free space decay rate. However, deriving the local density of states of the EM field in more complex scenarios, which involves the calculation of the imaginary parts of the dyadic Green's function (Novotny and Hecht, 2006;Scheel and Buhmann, 2008;Bennett and Buhmann, 2020;Stourm et al, 2020), can be computationally challenging. Although such calculations can aid the design of photonic devices, they do not provide much physical intuition.…”