Graduate Research

Optical Microsystems
Jack-Li-Ying Yao-Raghavendra-Avinash-Kamal

The research areas include modeling, design, process development and testing of optical MEMS devices for different bio applications based on different sensing methods, such as, reflection using micromirror, absorbance, evanescence, diffraction, etc. Some of the designs of micromirror and waveguides fabricated based on SOI are shown in Figures, for reference.

Dynamic characterization of microstructures using acousto-optic modulated stroboscopic interferometer

The Acousto-Optic-Modulated-Stroboscopic-Interferometer (AOMSI) is an innovative tool that can be employed to investigate the above mentioned characteristic for a given environmental condition. In this work, an optical non-contact system employing an Acousto-Optic-Modulator (AOM) to conduct dynamic characterization of MEMS structures is presented. The method is applied to atomic force microscope (AFM) cantilevers for demonstration purposes.

Post processed interferograms of the vibrational motion of an AFM cantilever for I and II mode.

Mirau interferometry

A simplified analytical approach is used to predict the static deflections and dynamic behavior of a microbridge subjected to uneven electrostatic fields caused by multiple electrostatic actuators. However, the beam model only can predict the static deformation in one direction. The microstructures in MEMS devices are soft and easily deformable. The uneven distribution of the electrostatic forces will cause the microstructure deforming in direction along length and width. Sometimes, the influence in the width direction cannot be neglected, especially when ratio between width and length is not very small. Mirau interferrometry is used for experimentation.

3D phase map and predicted corresponding static deflection.

Comparison of predicted and experimental static deflections, when voltages applied only at the central electrode.