Optomechanics with Sub-wavelength Gratings and Quantum Dots
I will describe two experiments underway with the goal of laser-cooling a fabricated mechanical oscillator toward the quantum ground state. In a first experiment, we fabricate a sub-wavelength grating structure in a silicon nitride membrane to create a mechanically compliant, highly reflective mirror, with a very high mechanical quality factor. We then use this grating as one mirror of a Fabry-Perot cavity, where radiation pressure couples the optical and mechanical degrees of freedom. I will discuss the optomechanical properties of these devices, including the prospects for ground-state cooling. In a second experiment, self-assembled quantum dots are used to read out mechanical motion by means of resolved sidebands in the fluorescence spectrum. This system is a solid-state analog of a trapped ion, in which the motional coupling to the optical field is provided by the strain-dependence of the deformation potential.