| AVS 61st International Symposium & Exhibition | |
| MEMS and NEMS | Wednesday Sessions |
| Session MN-WeM |
| Session: | Optomechanics, Photonics, and Quantum Nanosystems |
| Presenter: | Marcel Pruessner, Naval Research Laboratory |
| Authors: | M.W. Pruessner, Naval Research Laboratory D. Park, Naval Research Laboratory T.H. Stievater, Naval Research Laboratory D.A. Kozak, NRC Postdoc (Naval Research Lab) W.S. Rabinovich, Naval Research Laboratory |
| Correspondent: | Click to Email |
We present a compact footprint, fully-integrated nano-opto-mechanical system with strong evanescent field interaction. Silicon nitride films with sub-wavelength thickness (tSi3N4<λ/4nSi3N4) enable low-loss waveguides [1] as well as complex photonic circuits [2], e.g. directional couplers, Mach-Zehnder interferometers, microring cavities [3], nanobeam cavities [4], etc. Furthermore, the thin core layer and air top cladding allow access to the waveguide’s evanescent field, which can be tailored by simply varying the Si3N4 core layer deposition thickness. We previously demonstrated evanescent field interactions in these structures using a tapered fiber as an off-chip perturber [2] and by performing absorption spectroscopy on a number of chemical analytes present near the waveguide [3].
We now build upon our previous work [2,3] by fabricating a suspended tensile microbridge (SiNX) just above the waveguide surface (gap≈100-300nm) to achieve strong interactions between optical and mechanical structures in a fully-integrated device. For example, displacement of the mechanical perturber (microbridge) modifies the waveguide’s effective index so that the nano-opto-mechanical system acts as a high-resolution displacement sensor in which determination of the change in effective index is a measurement of displacement. At the same time, the change in the waveguide effective index as a function of displacement implies an optical force that acts on the microbridge [5].
Our nano-opto-mechanical system is compact and occupies a footprint that is essentially determined only by the waveguide since the mechanical structure is suspended directly above it. This vertical architecture enables us to optimize the optical and mechanical structures independently. Although simple, the opto-mechanical system enables complex interactions with a variety of potential applications including displacement sensing, optical-force reconfigurable photonics, and opto-mechanical oscillators. The compact footprint enables large-scale integrated opto-mechanical systems on a chip.
We will present the basic approach of our nano-opto-mechanical system, design and fabrication details, simulations to support strong evanescent field interaction, and initial experimental results demonstrating a strong interaction in chip-scale opto-mechanical structures.