MEMS Devices for Circumferential-scanned Optical Coherence Tomography Bio-imaging

Abstract

The optical coherence tomography (OCT) is a fundamentally new type of non-invasive optical imaging modality with capability of providing 2D/3D high resolution in vivo and in situ images and excellent optical sectioning for imaging multilayer microstructures of internal organs. A bimorph electrothermal actuation-based MEMS micromirror integrated OCT probe is developed and introduced first. For some clinical applications, full circumferential scanning (FCS) is highly desired, thus a pyramidal polygon MEMS micro-scanner is developed together with a foul-pieces-in-one fiber-pigtail GRIN lens bundle to meet this requirement. In this thesis, a cascaded chevron-beam electrothermal actuator based MEMS micro-scanner; two types of electrostatic actuation MEMS micro-scanners were developed including an electrostatic double T-shaped spring mechanism-based MEMS micro-scanner and an electrostatic resonating micro polygonal scanner . All of these three designs can realize near-full circumferential scanning, but only the electrostatic type MEMS micro-scanners have potentials to be commercialized due to its clinic-compatible surface temperature.