@article{1484222,
      recid = {1484222},
      author = {Hillberry, Logan Edward,},
      title = {Optically trapped microspheres as sensors of mass and  sound : Brownian motion as both signal and noise /},
      pages = {1 online resource (xvi, 115 pages) :},
      note = {"Doctoral thesis accepted by the University of Texas at  Austin, USA."},
      abstract = {This thesis makes significant advances in the use of  microspheres in optical traps as highly precise sensing  platforms. While optically trapped microspheres have  recently proven their dominance in aqueous and vacuum  environments, achieving state-of-the-art measurements of  miniscule forces and torques, their sensitivity to  perturbations in air has remained relatively unexplored.  This thesis shows that, by uniquely operating in air and  measuring its thermally-fluctuating instantaneous velocity,  an optically trapped microsphere is an ultra-sensitive  probe of both mass and sound. The mass of the microsphere  is determined with similar accuracy to competitive methods  but in a fraction of the measurement time and all while  maintaining thermal equilibrium, unlike alternative  methods. As an acoustic transducer, the air-based  microsphere is uniquely sensitive to the velocity of sound,  as opposed to the pressure measured by a traditional  microphone. By comparison to state-of-the-art  commercially-available velocity and pressure sensors,  including the world⁰́b9s smallest measurement microphone,  the microsphere sensing modality is shown to be both  accurate and to have superior sensitivity at high  frequencies. Applications for such high-frequency acoustic  sensing include dosage monitoring in proton therapy for  cancer and event discrimination in bubble chamber searches  for dark matter. In addition to reporting these scientific  results, the thesis is pedagogically organized to present  the relevant history, theory, and technology in a  straightforward way.},
      url = {http://library.usi.edu/record/1484222},
      doi = {https://doi.org/10.1007/978-3-031-44332-9},
}