Juan Miguel Auñón and Manuel Nieto-Vesperinas
Electromagnetic sources, e.g., lasers, antennas, diffusers, or thermal sources, produce a wave field that interacts with objects to transfer to them its momentum. We show that the photonic force exerted on a dipolar particle in the near field of a planar statistically homogeneous fluctuating source uniquely depends on and acts along the coordinate perpendicular to its surface. The gradient part of this force is contributed by only the evanescent components of the emitted field, its sign being opposite that of the real part of the particle polarizability. The nonconservative force is due to the propagating components, which are repulsive and constant. In addition, the source coherence length adds a degree of freedom since it largely affects these forces. The excitation of plasmons in the source surface drastically enhances the gradient force while slightly weakening the nonconservative scattering plus curl force. Hence these consequences obtained for random and partially coherent wave fields emitted by the sources addressed here should be relevant for particle manipulation at the subwavelength scale.
DOI
Electromagnetic sources, e.g., lasers, antennas, diffusers, or thermal sources, produce a wave field that interacts with objects to transfer to them its momentum. We show that the photonic force exerted on a dipolar particle in the near field of a planar statistically homogeneous fluctuating source uniquely depends on and acts along the coordinate perpendicular to its surface. The gradient part of this force is contributed by only the evanescent components of the emitted field, its sign being opposite that of the real part of the particle polarizability. The nonconservative force is due to the propagating components, which are repulsive and constant. In addition, the source coherence length adds a degree of freedom since it largely affects these forces. The excitation of plasmons in the source surface drastically enhances the gradient force while slightly weakening the nonconservative scattering plus curl force. Hence these consequences obtained for random and partially coherent wave fields emitted by the sources addressed here should be relevant for particle manipulation at the subwavelength scale.
DOI
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