Levitated microspheres

Search for new Interactions in a Microsphere Precision Levitation Experiment (SIMPLE):

Trapped microsphere

Photograph of a trapped microsphere in an early version of our apparatus

Over the past several years, techniques have been developed to optically levitate micron sized
spheres (“microspheres”) in a laser beam in vacuum.  In high vacuum, the microspheres can be isolated from their room temperature surroundings and their position can be controlled and measured optically using the transmitted laser light.  These techniques allow extremely tiny forces (as small as 10-21 N) acting on the sphere to be detected.

The development of these precision forces sensors can enable a variety of new experiments aimed at understanding some of the major unanswered questions in high energy physics.  We are currently applying these force sensors to the following experiments:

  • input_optics

    Photo of optics and vacuum chamber

    Tests of the inverse square law for gravity at distances as short as 1 micron

  • Searches for “millicharged particles” (particles with charges that are much smaller than 1 electron charge)
  • Tests of the neutrality of matter (i.e., is the sum of the proton, electron, and neutron charge exactly 0?)
  • Searches for new forces mediated by dark photons or other new, weakly coupled particles


We are currently building a new setup to use these force sensors to search for physics beyond the Standard Model at Wright Lab at Yale.  We have projects available for students interested in this research — see the Contact page for how to get involved!

Additional information:

Article and video on our experiment from Quanta magazine
Recent publications
Recent Presentations:

  • Talk at KITP, Santa Barbara, CA, April 2018
  • Talk at “Dark energy in the laboratory,” Kavli Royal Society at Chicheley Hall, UK, April 2016