Principal Investigators: Todd H. Stievater, Marcel W. Pruessner, and William S. Rabinovich, opticalmems@nrl.navy.mil

We are investigating the properties of micro/nano-opto-mechanical systems and subwavelength optical structures for next-generation photonics technologies. The high-index contrast and small feature sizes afforded by new precision lithography technologies in semiconductors and low-loss dielectric materials enable the creation of new nanoscale optical devices. At the same time, optical interferometric techniques are simple, yet exquisitively sensitive methods to read-out MEMS sensors and actuators, while micromechanical and nanomechanical displacement is proving to be an ideal method to achieve large phase or amplitude changes for integrated optical systems. In addition, photonic structures that are wavelength-scale or smaller enable the study of fascinating new properties, such as enormous form birefringence, huge evenescent fields, cavity-enhanced optical forces, and geometry-dependent phonon-polaritonics.

We are taking advantage of these properties to develop revolutionary new photonics technologies, all based on optical characteristics that are impossible to achieve in macroscopic systems. Our fundamental investigations of topics such as nanoslab waveguiding, coupled opto-mechanical oscillation, and photothermal spectroscopy are investigated with an eye towards U. S. Navy applications in areas such as microwave photonics, chemical sensing, and free-space optical communication.

Specific areas of research include:

  • Microwave Photonics and Electro-Optics: High-index contrast semiconductor waveguides offer exciting new ways to take advantage of the electro-optic properties of III-V materials. Also, silicon and silicon nitride waveguides form the basis of our research efforts in passive and thermo-optic components for microwave photonics, such as filters, combiners, switches, and delays.
  • Semiconductor Nonlinear Optics: Suspended semiconductor waveguides are characterized by strong confinement with low loss and offer exciting new ways to take advantage of the nonlinear and polaritonic properties of III-V materials.
  • Integrated Cavity Optomechanics: Low-intensity light can exert a significant force on micro- and nano-mechanical structures, especially in microcavities and highly-evanescent waveguides. We are studying these opto-mechanical forces in novel, integrated semiconductor nanostructures.
  • Photonic Chemical Sensing: We are investigating interferometric and spectroscopic techniques to interrogate microbridges and microcantilevers that have been coated with functionalized materials. Also, we are fabricating highly evanescent dielectric waveguide microcavities to spectroscopically sense and detect vapor-phase molecules at trace concentrations.
  • Nonmechanical Beam-Steering: Controlling the relative optical phase of waveguide arrays enables nonmechanical beam-steering for off-chip free-space applications. Our investigations of phase and amplitude control in arrayed high-index contrast silicon waveguides will shed light on the ultimate achievable limits of steering angle, beam quality, and divergence.