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| Author(s): |
Débora Princepe
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin |
| Defense date: | 2018-01-30 |
| Examining board members: |
Newton Cesário Frateschi;
Felippe Alexandre Silva Barbosa;
Lucas Heitzmann Gabrielli;
Paulo Alberto Nussenzveig;
Ben Hur Viana Borges
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| Advisor: | Gustavo Silva Wiederhecker; Newton Cesário Frateschi |
| Abstract | |
Optomechanical and electromechanical systems based on III-V semiconductor materials have become a topic of high interest. Beyond the attractive material properties, this attention is mainly due to the possibility of integrating an optomechanical resonator with a laser cavity in a single device. Theoretical and experimental investigation show that interaction in these hybrid systems can provide enhancement of the optomechanical cooling rate, control of the laser emission, among other effects. In this thesis, we present our work on active optomechanical resonators built on semiconductor material. Under a semi-classical approach, a model based on the laser rate equations coupled to a harmonic oscillator was developed, with both optical resonance and loss modified by the cavity deformation. This model differs from usual Cavity Optomechanics since both the driving field and the detuning are absent, leading to a control done by current injection. A novel coupling model between mechanical vibration and laser relaxation oscillation is derived from the system dynamics, such that the amplification regime is achieved for certain value of overall optomechanical strength. Under this condition, photons and mechanical vibration present self-sustained oscillation -- therefore, a self-pulsed laser is obtained. Instrumentation for the fabrication and measurement of an optomechanical laser was developed based on microdisk geometry with optical pump and purely dispersive optomechanical coupling. We then present an investigation of the relevant parameters for the design of an optomechanical laser cavity based on GaAs platform. Laser emission and optomechanical interaction are predicted and observed in microdisks with quantum well gain medium. We discuss the significant challenges involved in obtaining an optomechanical laser. Finally, we present the design of a realistic optomechanical laser with a strong enhancement of the optomechanical coupling employing both dispersive and dissipative mechanisms. Essentially an active optomechanical bullseye with very strong dispersive coupling is combined with a dissipative structure, an external metallic ring. The dispersive interaction is enhanced by the confinement of mechanical and optical modes near the disk edge and the dissipative coupling effect is provided by near field interaction with the metallic ring separated by a small gap. This novel dissipative optomechanical device is shown to potentially result in a realistic optomechanical laser (AU) | |
| FAPESP's process: | 11/18945-6 - Active cavities optomechanics |
| Grantee: | Débora Princepe |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |