Figure 2.

Repulsive force dependence on the permittivity tensor components. (a) Parametric plot of the quasistatic repulsion condition (shaded area) for the particle in air |ε_x||ε_z|<1 as a function of the real parts of the permittivities and for different values of their imaginary parts . (b) Parametric plot of the exact vertical force calculated with Equation (1) for a vertically oriented dipole situated at a height h=0.01λ over a uniaxial substrate for two different values of losses. (c) Same as b but for a height h = 0.1λ, where the quasistatic condition does not apply. The permittivity range of the repulsive force is broader than in the quasistatic approximation shown with a dashed line.