2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/136202Based on the Lifshitz theory we show that the illumination of one (Si) plate in the three-layer systems Au--ethanol--Si, Si--ethanol--Si and $α$-Al${}_2$O${}_3$--ethanol--Si with laser pulses can change the Casimir attraction to Casimir repulsion and vice versa. The proposed effect opens novel opportunities in nanotechnology to actuate the periodic movement in electro- and optomechanical micromachines based entirely on the zero-point oscillations of the quantum vacuum without the action of mechanical springs.9 pages, 4 figures, to appear in J. Phys. A: Math. Theor. (Fast Track Communication)Quantum Physicstext