Prof. Viktor Dodonov, Full Professor, Institute of Physics and International Center for Physics, University of Brasilia, Brazil

Title: Dynamical Casimir effect meets material Science

Abstract: I consider different proposals to observe the so called Dynamical Casimir effect in cavities, changing their optical lengths by means of fast time variations of material properties (dielectric permeability or conductivity) of thin slabs attached to the cavity walls. The emphasis is made on the case of semiconductor slabs excited by short laser pulses. Considering the evolution of the classical electromagnetic field in this case, an approximate analytical solution for an infinite set of coupled ordinary differential equations for the mode amplitudes is found under certain simplifying assumptions. According to this solution, an amplification of the initial field can be possible provided the induced dielectric permeability can become negative with a big absolute value. Evaluations of the feasibility of such a scenario are given. Another possibility of parametric amplification of the microwave vacuum field in a cavity is to use a nonlinear crystal whose refractive index is modulated by periodic high-intensity short laser pulses. In this case, the total number of created ‘Casimir quanta’ depends neither on the laser beam shape, nor on the duration or power of individual pulses, but it depends on the total energy of all the pulses, provided the duration of each pulse is much shorter than the period of field oscillations in the selected resonant mode. This scheme can be feasible if reliable materials with high nonlinear coefficients can be found.

Keywords: semiconductors, nonlinear optical materials, time-dependent conductivity and refraction index, electromagnetic cavity, thin slabs