Mesures d'alta precisió de camp magnètic i sincronització en cavitats optomecánicas
- Autores: Martín Colombano Sosa
- Directores de la Tesis: Daniel Navarro Urrios (dir. tes.), Marius. V Costache (codir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2020
- Idioma: español
- ISBN: 9788449095214
- Tribunal Calificador de la Tesis: Ferran Macià Bros (presid.), Alessandro Tredicucci (secret.), Francisco Torres Canals (voc.)
- Programa de doctorado: Programa de Doctorado en Física por la Universidad Autónoma de Barcelona
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
Mechanical resonators are one of the most fundamental and omnipresent physical systems at all scales. They play a substantial role in radio-signal processing and sensing. In the last decades, efforts have been made toward the investigation of different approaches to control, to couple, and to read out their motion. At the micrometre- and nanometre-scale, the first approach that emerged was to couple mechanical structures to electrical circuits. More recently, researchers have investigated the use of electromagnetic radiation to control and probe mechanical elements. This field, called Optomechanics, has been used to explore fundamental physics problems like testing quantum mechanics on heavy mass structures or for quantum information processing. Many of these experiments require the mechanical resonator at the ground state of motion, but this can only happen at extremely low temperatures and under very specific conditions. My thesis aim is to unravel other important aspects of coupling light to mechanical objects that do not require to operate at the ground state. In particular, I will discuss two experiments performed at room temperature focused on applying optomechanics to technological challenges.
The first experiment is related to the ability of optomechanical systems to detect small forces applied to a mechanical resonator. We employ a microsphere optomechanical sensor to detect the force induced by an extremely small magnetic field. The force is produced by a resonant phenomena that involve magnons and phonons on ferromagnetic material. The magnetic field sensor is characterized by a pico-Tesla peak sensitivity with a bandwidth of 100 kHz. Also, the tunability of the frequency response rises the device frequency operation up to a dynamical range of 1.1 GHz. This device is a proof of concept that opens a window to develop ultra-high sensitive optomechanical magnetometers, which is crucial in many areas covering geology, medical imaging systems, or defense.
The second experiment of this thesis describes a fundamental challenge of nanoscale physics that is the synchronization of two optomechanical cavities connected by a weak coupling. We show that exploiting the interaction between the mechanical elements and the nonlinearity of the light field, we can strategically modify the dynamical state of the oscillators. We show that the nanobeams are individually oscillating in a coherent, high amplitude and sustained state. We also experimentally demonstrate that the system evolves to a regime where the two oscillators are fully synchronized in anti-phase. The results of this experiment could be setting a base for low-noise communications between optomechanical devices.
