This study proposes a nanophotonic structure that supports the generation and enhancement of the lateral Casimir-Polder (CP) force acting on atoms. By applying the two-dimensional anisotropic material, we demonstrate that both the spontaneous decay rate and the emission pattern of the atom exhibit distinct features by manipulating the parameters of the system. In particular, the exact numerical solutions of population dynamics reveal the occurrence of Rabi oscillations in the strong atom-field coupling case, where the Markovian results fail to describe this phenomenon. We also show that the asymmetric spatial distribution of the in-plane dipole radiation into surface plasmon modes is achievable for the system under consideration. Based on these intriguing properties, we predict the generation of the lateral CP force, where the transient evolution of the force indicates the periodical variation in both the direction and the amplitude under strong light-atom interaction conditions. Our findings have potential applications for novel optical nanotechnologies and devices, which provide a method for atom manipulation and trapping.
This study proposes a nanophotonic structure that supports the generation and enhancement of the lateral Casimir-Polder (CP) force acting on atoms. By applying the two-dimensional anisotropic material, we demonstrate that both the spontaneous decay rate and the emission pattern of the atom exhibit distinct features by manipulating the parameters of the system. In particular, the exact numerical solutions of population dynamics reveal the occurrence of Rabi oscillations in the strong atom-field coupling case, where the Markovian results fail to describe this phenomenon. We also show that the asymmetric spatial distribution of the in-plane dipole radiation into surface plasmon modes is achievable for the system under consideration. Based on these intriguing properties, we predict the generation of the lateral CP force, where the transient evolution of the force indicates the periodical variation in both the direction and the amplitude under strong light-atom interaction conditions. Our findings have potential applications for novel optical nanotechnologies and devices, which provide a method for atom manipulation and trapping.
We study the spontaneous emission of an excited atom close to an optical nanofiber and the resulting scattering forces. For a suitably chosen orientation of the atomic dipole, the spontaneous emission pattern becomes asymmetric and a resonant Casimir-Polder force parallel to the fiber axis arises. For a simple model case, we show that such a lateral force is due to the interaction of the circularly oscillating atomic dipole moment with its image inside the material. With the Casimir--Polder energy being constant in the lateral direction, the predicted lateral force does not derive from a potential in the usual way. Our results have implications for optical force measurements on a substrate as well as for laser cooling of atoms in nanophotonic traps.
The Casimir-Polder (CP) force acting on a V-type three-level atom which is initially prepared in two different kinds of superposition states, i.e., subradiant and superradiant states, is investigated. The influence of quantum interference on force evolution due to two-dipole transitions is analyzed in detail. It is found that the orientation of the atomic dipole moment has significant influence on the Casimir-Polder force and consequently its evolution. For the ideal degenerate V-type atom with two parallel dipoles, quantum interference leads to population trapping as well as the cancellation of the CP force when the atom is prepared initially in a subradiant state. However, the result changes when we consider the practical Zeeman V-type atom whose two dipole moments are perpendicular to each other. Since quantum interference in such an atom must occur in an anisotropic environment, it is possible to trap atomic population and enhance the CP force simultaneously by preparing the atom initially in sub-radiant states. In principle, our results can be found in an arbitrary anisotropic environment, and here we describe a structure containing left-handed materials to highlight our findings.
Influence of the Casimir-Polder force on a slowly moving atom near a left-handed slab is discussed.We focus on an initially excited atom and its dynamic evolution during the spontaneous decay process.The left-haned slab is adopted based on two factors:(1) It provides a relatively stronger Casimir-Polder force on the excited atom far away from the interface,and(2) it can lead to an inhibited spontaneous decay rate within such a region.Therefore,we can discuss the dynamic evolution of atoms acted only by the Casimir-Polder force.The dynamic evolution discussed here includes both the evolution of atomic population and the atomic displacement.As the Casimir-Polder force depends on the atomic population,while the decay rate is related to the atomic positions,the atomic dynamic evolution is determined by its initial conditions,i.e.its position and volecity.We choose two initial positions for discussion,i.e.(1) the position with the maximum resonant Casimir-Polder force,and(2) the edge of the resonant Casimir-Polder force of the atom with dipole parallel to the interface.Furthermore,we also consider two kinds of orientations of atomic dipole,i.e.parallel and normal to the interface.It is found that the atom can be repulsed away from a surface by the Casimir-Polder force with a proper initial velocity in certain dipole orientaion during the sponatneous decay process.As the atomic dynamics depends on the orientation of the atom dipole momentum,our result can be used as a reference to distinguish atoms with different dipole momenta.Though the force discussed here exists during the spontaneous decay process,it is much different from the recoil force of the atom when it emits a photon during the spontaneous decay.The statistical average of the recoil force is null,but that of the resonant Casimir-Polder force is not.After reasonable estimation,such a Casimir-Polder force can counteract the thermal fluctuation of temperature of 15 μK during sponatneous decay.If combined with other constraint methods,it is helpful to control the dynamics of an atom more efficiently.
Influence of the Casimir-Polder force on a slowly moving atom near a left-handed slab is discussed. We focus on an initially excited atom and its dynamic evolution during the spontaneous decay process. The left-haned slab is adopted based on two factors: (1) It provides a relatively stronger Casimir-Polder force on the excited atom far away from the interface, and (2) it can lead to an inhibited spontaneous decay rate within such a region. Therefore, we can discuss the dynamic evolution of atoms acted only by the Casimir-Polder force. The dynamic evolution discussed here includes both the evolution of atomic population and the atomic displacement. As the Casimir-Polder force depends on the atomic population, while the decay rate is related to the atomic positions, the atomic dynamic evolution is determined by its initial conditions, i.e. its position and volecity. We choose two initial positions for discussion, i.e. (1) the position with the maximum resonant Casimir-Polder force, and (2) the edge of the resonant Casimir-Polder force of the atom with dipole parallel to the interface. Furthermore, we also consider two kinds of orientations of atomic dipole, i. e. parallel and normal to the interface. It is found that the atom can be repulsed away from a surface by the Casimir-Polder force with a proper initial velocity in certain dipole orientaion during the sponatneous decay process. As the atomic dynamics depends on the orientation of the atom dipole momentum, our result can be used as a reference to distinguish atoms with different dipole momenta. Though the force discussed here exists during the spontaneous decay process, it is much different from the recoil force of the atom when it emits a photon during the spontaneous decay. The statistical average of the recoil force is null, but that of the resonant Casimir-Polder force is not. After reasonable estimation, such a Casimir-Polder force can counteract the thermal fluctuation of temperature of 15 μupK during sponatneous decay. If combined with other constraint methods, it is helpful to control the dynamics of an atom more efficiently.
Plasmonic nanostructures enable strong, localized enhancement of electromagnetic fields, making them powerful platforms for mediating light interactions with quantum emitters (QEs) at the nanoscale. However, the spatial inhomogeneity of these fields imposes sub-nanometric precision requirements on emitter placement, limiting the robustness and scalability of quantum photonic systems. Here, we investigate how permanent dipole moments (PDMs) in polar QEs affect their optical response in such environments. In our model, PDMs introduce a nonlinear dependence of coupling strength and spontaneous emission rate on the local field amplitude. Our simulations of QEs near a plasmonic nanosphere show that PDMs can markedly reduce spatial variations in interaction strength and decay rate, yielding stabilized Rabi oscillations and extended coherence times even in strong-field gradients. Exploiting systems with PDMs thus offers a route to more robust QEs in confined optical fields, with potential benefits for quantum control, information processing, and nanophotonic device design.
The transient Casimir-Polder force on a two-level atom introduced into a three-dimensional, inhomogeneous, generally nonreciprocal environment is evaluated using non-Markovian Weisskopf-Wigner theory in the strong- and weak-coupling regimes. Ground-state and excited atoms are shown to decouple into two separate initial-value problems, and both the short-time and long-time atomic population and force are evaluated. The results are compared with various Markov approximations of the Weisskopf-Wigner theory and with previous Markov results from the Heisenberg picture.