This project advanced fundamental science of nanomechanical resonators and helped design novel nanomechanical resonators, solving some of the technological challenges in front of making these devices useful to society. A nanomechanical resonator, or a nanoelectromechanical system (NEMS),  is a mechanical element with sub-micron linear dimensions that vibrates in one of its resonant modes.  These devices give nanotechnologists access to an unprecedented physical parameter space, with a number of high-impact potential applications, such as bio-threat detection, environmental monitoring and medical diagnostics. However, before these devices can be adopted in applications, a number of scientific and technological challenges must be solved. Most prominent of these problems are coupling to the tiny vibrations of NEMS and operating distributed arrays of NEMS.  

In the project, the first problem was solved by a variety of approaches involving confined light waves in an optical waveguide or circuit. First, a NEMS resonator was integrated to an optical fiber, allowing for the detection of the vibratory motion by scattering the confined light waves around the optical fiber. This method provided a very good sensitivity for detection as well as possibilities for making practical devices. In a second set of experiments, a NEMS resonator was integrated to an optical resonator on a Silicon chip, resulting in greatly enhanced detection sensitivity. Briefly, the optical resonator is a micron scale disk structure, which confines light waves in a whispering gallery mode. Thus, light is stored on the chip for longer periods and the interaction between the NEMS resonator and the light field is stronger, resulting in an increased detection sensitivity for motion. The project demonstrated both detection methods successfully, opening up new approaches for coupling to the motion of NEMS resonators.  In developing and demonstrating these devices, progress was made in fundamental optical sciences in the area of near-field optics.

Progress was also made in the project on the second challenge of arrayed NEMS operation. Here, a fiber-taper transducer interface, which relied upon the evanescent optomechanical interactions described above, was developed. Using this approach, resonances from an array of 63 NEMS resonators was detected with good sensitivity.

The development of versatile arrayed NEMS devices have broader impacts to society. Because a single nanodevice (e.g., a single NEMS resonator) is typically very inefficient in a macroscopic world application, arrays of nanodevices are the way of the future. The educational and outreach impacts can be summarized as follows: i) outreach to high school students and undergraduate students encouraged these students to pursue future careers in science and engineering; ii) the research was disseminated at the undergraduate level; iv) two Ph.D. students completed their degrees based on research performed as part of the project.

Last Modified: 05/22/2013
Modified by: Kamil Ekinci