Enhancement of the quadrupole interaction of an atom with guided light of an ultrathin optical fiber

Abstract

We investigate the electric quadrupole interaction of an alkali-metal atom with guided light in the fundamental and higher-order modes of a vacuum-clad ultrathin optical fiber. We calculate the quadrupole Rabi frequency, the quadrupole oscillator strength, and their enhancement factors. In the example of a rubidium-87 atom, we study the dependencies of the quadrupole Rabi frequency on the quantum numbers of the transition, the mode type, the phase circulation direction, the propagation direction, the orientation of the quantization axis, the position of the atom, and the fiber radius. We find that the root-mean-square (rms) quadrupole Rabi frequency reduces quickly but the quadrupole oscillator strength varies slowly with increasing radial distance. We show that the enhancement factors of the rms Rabi frequency and the oscillator strength do not depend on any characteristics of the internal atomic states except for the atomic transition frequency. The enhancement factor of the oscillator strength can be significant even when the atom is far away from the fiber. We show that, in the case where the atom is positioned on the fiber surface, the oscillator strength for the quasicircularly polarized fundamental mode HE${}_{11}$ has a local minimum at the fiber radius $a\simeq 107$ nm, and is larger than that for quasicircularly polarized higher-order hybrid modes, TE modes, and TM modes in the region $a<498.2$ nm.

References in corpus (10)

• Chiral Quantum Optics
• Quantum computing with trapped ions
• Chiral nanophotonic waveguide interface based on spin-orbit coupling of light
• Conservation of the spin and orbital angular momenta in electromagnetism
• Lamb-Dicke spectroscopy of atoms in a hollow-core photonic crystal fibre
• Angular Momentum Transfer in Interaction of Laguerre-Gaussian Beams with Atoms and Molecules
• Anisotropy in scattering of light from an atom into the guided modes of a nanofiber
• Propagation of nanofiber-guided light through an array of atoms
• Spontaneous radiative decay of translational levels of an atom near a dielectric surface
• Channeling of spontaneous emission from an atom into the fundamental and higher-order modes of a vacuum-clad ultrathin optical fiber