The time evolution of the radiation pressure forces due to the action of a laser light on two-level atom moving inside a long hollow cylinder with a rectangular cross-section of sub-wavelength dimensions a × b is presented.This evolution is considered when the frequency of the light is comparable to a dipole allowed transition frequency.In this limit, the decay emission Γ is possible only via a very small number of modes.From the solutions of the Bloch equations in the dynamic regime, we nd that the transient regime, applicable from the instant the laser is switched on.This is important for the gross motion, provided that the upper-state lifetime Γ -1 is relatively long while the steady-state regime, formally such that t Γ -1 , is appropriate for the evaluation of the forces and the dynamics for large Γ .Signicant variations of the characteristics of the system are emphasized.These features are illustrated using typical parameters for the case of Eu 3+ that has a particularly small Γ .The time evolution of the radiation pressure forces due to the action of a laser light on two-level atom moving inside a long hollow cylinder with a rectangular cross-section of sub-wavelength dimensions a × b is presented.This evolution is considered when the frequency of the light is comparable to a dipole allowed transition frequency.In this limit, the decay emission Γ is possible only via a very small number of modes.From the solutions of the Bloch equations in the dynamic regime, we nd that the transient regime, applicable from the instant the laser is switched on.This is important for the gross motion, provided that the upper-state lifetime Γ -1 is relatively long while the steady-state regime, formally such that t Γ -1 , is appropriate for the evaluation of the forces and the dynamics for large Γ .Signicant variations of the characteristics of the system are emphasized.These features are illustrated using typical parameters for the case of Eu 3+ that has a particularly small Γ .

Acta Physica Polonica AApr 1, 20131 citation

Atomic motion in hollow submicron circular cylinders

S. Al‐Awfi, M. Babiker

The motion of atoms inside a long hollow cylindrical waveguide with a circular cross section is investigated. The guide is assumed to have subwavelength dimensions, in which case the spontaneous decay process is effected only by emission of a few possible cavity modes. The characteristics of the atomic motion in the guide are explored in the presence of an excited waveguide mode. We show that the atomic motion in this case is determined by an axial channelling force and a trapping dipole force, plus a quantized light torque associated with the orbital angular momentum property of excited waveguide modes of order $\mathcal{l}>0.$ It is predicted that in addition to its axial motion, an atom subject to such a mode should be trapped radially in a vibrational state and should exhibit interesting rotational features due to the light torque, including a rotational frequency shift.The motion of atoms inside a long hollow cylindrical waveguide with a circular cross section is investigated. The guide is assumed to have subwavelength dimensions, in which case the spontaneous decay process is effected only by emission of a few possible cavity modes. The characteristics of the atomic motion in the guide are explored in the presence of an excited waveguide mode. We show that the atomic motion in this case is determined by an axial channelling force and a trapping dipole force, plus a quantized light torque associated with the orbital angular momentum property of excited waveguide modes of order $\mathcal{l}>0.$ It is predicted that in addition to its axial motion, an atom subject to such a mode should be trapped radially in a vibrational state and should exhibit interesting rotational features due to the light torque, including a rotational frequency shift.

Physical Review AFeb 10, 200024 citations

\mathcal{l}>0.

It is predicted that in addition to its axial motion, an atom subject to such a mode should be trapped radially in a vibrational state and should exhibit interesting rotational features due to the light torque, including a rotational frequency shift.