Enhacement of the Casimir between Silicon by Irradiation
Abstract Book of the XXIII IUPAP International Conference on Statistical Physics, Genova, Italy, (9-13 July 2007)Abstract
We discuse two topics relevant to the Casimir force (retarded van der Waals force). First, we consider the enhacement of the Casimir between silicon plates by irradiation. Irradiation generates free carriers inside silicon and it can cause enhancement of the Casimir force between silicon membranes. We study numerically the temporal behavior of the Casimir force between two parallel silicon membranes after irradiating the surface with UV pulse laser. In the calculation, the free carrier density is obtained by solving the diffusion equation with the generation and recombination terms, and the dielectric function of the illuminated silicon is calculated from them by employing the Drude model. Based on the Lifshitz theory accounting for thickness of the slabs, we calculate the Casimir force as a function of time and consider the finite size effect of the thickness. Second, we consider the influence of optical adsorption on the Casimir force acting between a metallic sphere and a semiconductive plate illuminated with Gaussian light beam is considered.
The Casimir torque and the lateral Casimir force result form the inhomogeneous photonionization. Taking into account the spatial inhomogeneousness of the plasma frequency in the semiconductive plate, the dependence of the Casimir force on the distance between
the optical axis and the center of the sphere is computed within the proximity force approximation.