Date of Award

6-17-2017

Document Type

Thesis - SCU Access Only

Publisher

Santa Clara : Santa Clara University, 2017.

Department

Bioengineering

First Advisor

Emre Araci

Abstract

We developed a miniature angular scanner for optical components (ASOC) (i.e. lenses and mirrors), which is actuated using pressure. This novel technology will improve the field-of-view (FoV) in current forward-facing optical probes. We focused on developing an optical probe that could scan 30° field-of-view, which could potentially increase the viewing area almost an order of magnitude. As steps towards developing a clinically useful probe, we have characterized i) durability ii) control accuracy iii) and optical clarity of the device. We have utilized two different commercially available silicone materials: Polydimethylsiloxane (PDMS - RTV615) from Momentive Inc. and Ecoflex from Smooth-On Inc (Ecoflex 00-10). In our tests, we have varied the physical parameters such as Young’s modulus and device architecture. We found that using a lower Young’s modulus material (Ecoflex) significantly reduced the actuation pressure, therefore it is preferable to more rigid materials. We also found that as the device aspect ratio (wall height: wall width) increases, the actuation pressure has increased. By using 3D printed molds we were able to achieve an aspect ratio of four. To achieve optical clarity we have carefully filled the chambers of ASOC, made of PDMS, with its liquid pre-polymer to match the refractive index of chambers with the walls. We have developed a protocol to fill the small chambers with the highly viscous pre-polymer in a bubble free manner to eliminate the optical scattering sites. For most optical applications where lenses have to be used, the PDMS device is more viable than the Ecoflex device due to the optical clarity advantage. For future purposes, a material that had combined benefits of the Ecoflex and PDMS materials would be ideal in completing all goals with a single device.

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