Optomecânica de cavidades em discos de silício e discos nanosestruturados de silício

Author(s)

Felipe Gustavo da Silva Santos

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin
• Defense date: 2017-06-09

Examining board members

Thiago Pedro Mayer Alegre; Lino Misoguti; Christiano José Santiago de Matos; José Antonio Roversi; Lucas Heitzmann Gabrielli

• Advisor: Gustavo Silva Wiederhecker; Thiago Pedro Mayer Alegre

Abstract

Cavity optomechanics has proven to be a very rich field of study with applications reaching gravitational wave interferometers, fundamentals of quantum mechanics, quantum simulation, synchronization, all-optical tunable optical filters, optical memories ¿ to cite a few. Among the many devices reported in the literature, microcavities integrated on chips offer a very promising alternative for studying dynamical effects due to the interaction between confined mechanical and optical waves. Among microcavities, disks and optomechanical crystals (based on photonic and phononic bandgap confinement) are very promising and frequently studied devices, each having unique advantages. In this thesis, we allow for disks to meet bandgap confinement in a novel optomechanical design, the bullseye. On one hand, we developed know-how on the fabrication and characterization of optomechanical silicon disks, reaching optical linewidth smaller than 1 GHz (quality factor of order 105). On the other hand, we show how the bullseye design can overcome some limitations of simple disk cavities in order to achieve the so called resolved sideband regime, in which the mechanical resonance frequency is larger than the optical linewidth. We used finite elements method simulations to deeply understand the bullseye¿s optomechanical properties, predicting high frequency (larger than 8 GHz) mechanical modes with vacuum optomechanical coupling rate (measure of the optical frequency shift induced by the mechanical ground state¿s fluctuations) as high as 200 kHz ¿ a value comparable to the current state-of-the-art. Finally, we experimentally demonstrate the bullseye¿s optomechanical properties in samples fabricated by CMOS-compatible processes, thus paving a new way towards massive commercial and research-related applications of cavity optomechanics (AU)

• FAPESP's process: 13/06360-9 - Optomechanical Cavities
• Grantee: Felipe Gustavo da Silva Santos
• Support Opportunities: Scholarships in Brazil - Doctorate