1. Department of Mechanical Engineering and the Materials Science and Engineering Program, The University of Texas at Austin, Austin, Texas 78712, United States
2. DARPA Center for Integrated Micro/Nano-Electromechanical Transducers (iMINT), United States
3. Departments of Physics and Electrical and Computer Engineering, Photonics Center, and Center for Nanoscience and Nanobiotechnology, Boston University, Boston, Massachusetts 02215, United States