Constructing a Levitated Microsphere Array and its Application to Dark Matter Searches

Arrays of optically levitated micron-sized, nanogram-mass spheres have many applications in precision measurements. For example, an array of levitated microspheres can enable improved searches for dark matter using mechanical oscillators. By monitoring the motion of the spheres for impulses of imparted momentum, we can search for composite dark matter particles. Arrays can also be utilized to improve background rejection for millicharged particle searches. We present a system which uses an acousto-optic deflector to levitate a two dimensional array of microspheres in vacuum. This array is composed of time-shared traps with independent control of each sphere's position and feedback. We study optically and electrically mediated intersphere interactions to better understand backgrounds inherent with this new tool.