Squeezing Optomechanics

Optomechanics studies the interaction between light and a mechanical resonator, enabled via radiation pressure. Employing a high finesse cavity it is possible to enhance this interaction, enabling the possibility of bringing macroscopic objects in a quantum superposition of states and possibly opening the way to the experi- mental study of quantum decoherence. The work carried out in this thesis consists in the developement and improvement of an experimental setup used to perform optomechanics experiment, that in the future will allow to experimentally investi- gate the foundations of quantum mechanics. The first part of this thesis deals with the developement of an optical system for cryogenic applications that matches the Gaussian mode of a SM optical fiber into a high Finesse optical cavity. We will discuss how a prototype has been designed and experimentally tested. In the second section will be investigated a technical problem encountered in the Pound-Drever-Hall (PDH) frequency stabilization setup implemented using optical fibers instead of free space optics. The presence of some wiggles in the PDH error signal, and a time dependent shift of its baseline makes difficult to lock the laser to the cavity for a sufficient amount of time to perform experiments. Numerical simulations and experiments will be performed in order to understand the origin of the problem, and to solve it. The last part of this work consists in the experimental study of the decay of a ther- momechanical squeezed state, a phenomenon that to the knowledge of the author has never been investigated yet. In particular we will create a thermal squeezed state by parametric modulation of the spring constant, and we will study its time evolution after we switch off this parametric modulation.