Hy-Q Seminar - Francesco Marin

Francesco Marin - Università degli Studi di Firenze

Title: Cavity opto-mechanics experiments at the University of Florence

Abstract: I will present the activity of the optomechanics group of the University of Florence, discussing in particular two experiments. The first one is a based on a cryogenic setup with a vibrating SiN membrane inside an optical cavity. The mechanical oscillator is cooled and prepared in a squeezed state by parametric excitation. I will then highlight a typically quantum indicator of this state. The protagonist of the second experiment is a silica nanosphere levitating and oscillating in the potential created by an optical tweezer. Once positioned inside an optical cavity, the nanosphere interacts with the cavity modes of the electromagnetic field, through coherent dipole scattering. At low pressure, the system enters the quantum-coherent strong coupling regime. We observe the formation of two-dimensional polaritons (hybrid photonic-phononic modes), and we achieve the cooling of the oscillatory motion of the nanosphere down to an occupation numbers below unity.