Opto-Mechanics of deformable Fabry-Perot Cavities

We investigated the opto-mechanical properties of a Fabry-Perot cavity with a mirror mounted on a spring. Such a structure allows the cavity length to change elastically under the effect of light induced forces. This opto-mechanical coupling is exploited to control the amplitude of mechanical fluctuation of the mirror. We present a model developed in the classical limit and discuss data obtained in the particular case for which photo-thermal forces are dominant.Comment: 26 pages, 7 figure

Opto-Mechanics of deformable Fabry-Perot Cavities

We investigated the opto-mechanical properties of a Fabry-Perot cavity with a mirror mounted on a spring. Such a structure allows the cavity length to change elastically under the effect of light induced forces. This opto-mechanical coupling is exploited to control the amplitude of mechanical fluctuation of the mirror. We present a model developed in the classical limit and discuss data obtained in the particular case for which photo-thermal forces are dominant.Comment: 26 pages, 7 figure

Self-induced oscillations in an optomechanical system

We have explored the nonlinear dynamics of an optomechanical system consisting of an illuminated Fabry-Perot cavity, one of whose end-mirrors is attached to a vibrating cantilever. Such a system can experience negative light-induced damping and enter a regime of self-induced oscillations. We present a systematic experimental and theoretical study of the ensuing attractor diagram describing the nonlinear dynamics, in an experimental setup where the oscillation amplitude becomes large, and the mirror motion is influenced by several optical modes. A theory has been developed that yields detailed quantitative agreement with experimental results. This includes the observation of a regime where two mechanical modes of the cantilever are excited simultaneously.Comment: 4.5 pages, 3 figures (v2: corrected few typos

Photoelastic coupling in gallium arsenide optomechanical disk resonators

We analyze the magnitude of the radiation pressure and electrostrictive stresses exerted by light confined inside GaAs semiconductor WGM optomechanical disk resonators, through analytical and numerical means, and find the electrostrictive force to be of prime importance. We investigate the geometric and photoelastic optomechanical coupling resulting respectively from the deformation of the disk boundary and from the strain-induced refractive index changes in the material, for various mechanical modes of the disks. Photoelastic optomechanical coupling is shown to be a predominant coupling mechanism for certain disk dimensions and mechanical modes, leading to total coupling g$_{om}$ and g$_0$ reaching respectively 3 THz/nm and 4 MHz. Finally, we point towards ways to maximize the photoelastic coupling in GaAs disk resonators, and we provide some upper bounds for its value in various geometries

High frequency GaAs nano-optomechanical disk resonator

Optomechanical coupling between a mechanical oscillator and light trapped in a cavity increases when the coupling takes place in a reduced volume. Here we demonstrate a GaAs semiconductor optomechanical disk system where both optical and mechanical energy can be confined in a sub-micron scale interaction volume. We observe giant optomechanical coupling rate up to 100 GHz/nm involving picogram mass mechanical modes with frequency between 100 MHz and 1 GHz. The mechanical modes are singled-out measuring their dispersion as a function of disk geometry. Their Brownian motion is optically resolved with a sensitivity of 10^(-17)m/sqrt(Hz) at room temperature and pressure, approaching the quantum limit imprecision.Comment: 7 pages, 3 figure