Skip to content Skip to navigation


January 16, 2019 - 9:00am
PAB 102/103

Ph.D. Candidate:  Alexander Rider
Research Advisor:  Giorgio Gratta

Date: Wednesday, 1/16/2019
Time: 9:00 am
Location: PAB 102/103

Title: Measurements with Optically Levitated Microspheres

I discuss the development of optically levitated
microspheres as a tool for precision measurements and tests of fundamental
physics. Micron-scale dielectric spheres are trapped by the radiation pressure
at the focus of a Gaussian laser beam, where the optical suspension enables
thermal, electrical, and mechanical isolation from the surrounding environment
at high vacuum. Forces and torques can be measured from changes in the angle
and polarization of light both transmitted through and reflected by the trapped
particle. Additionally, the charge of the particle can be controlled with
single electron precision. We have used these methods for the following three
purposes: to search for fractionally charged particles and dark energy, to
develop measurement techniques for surface potentials, and to construct an
electrically driven micro-gyroscope.