Portable polarimetric fiber stress sensor system for visco-elastic and biomimetic material analysis

• Published in: Applied physics letters 2015-05, Vol.106 (19)
• Main Authors: Harrison, Mark C., Armani, Andrea M.
• Format: Article
• Language: English
• Subjects: Applied physics; Biomedical materials; Biomimetic materials; Control equipment; Curing agents; Elastomers; Modulus of elasticity; Nondestructive testing; Polarimeters; Polarimetry; Polarization; Polarizers; Polydimethylsiloxane; Silicone resins; Viscoelasticity
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4921243

Non-destructive materials characterization methods have significantly changed our fundamental understanding of material behavior and have enabled predictive models to be developed. However, the majority of these efforts have focused on crystalline and metallic materials, and transitioning to biomaterials, such as tissue samples, is non-trivial, as there are strict sample handling requirements and environmental controls which prevent the use of conventional equipment. Additionally, the samples are smaller and more complex in composition. Therefore, more advanced sample analysis methods capable of operating in these environments are needed. In the present work, we demonstrate an all-fiber-based material analysis system based on optical polarimetry. Unlike previous polarimetric systems which relied on free-space components, our method combines an in-line polarizer, polarization-maintaining fiber, and a polarimeter to measure the arbitrary polarization state of the output, eliminating all free-space elements. Additionally, we develop a more generalized theoretical analysis which allows more information about the polarization state to be obtained via the polarimeter. We experimentally verify our system using a series of elastomer samples made from polydimethylsiloxane (PDMS), a commonly used biomimetic material. By adjusting the base:curing agent ratio of the PDMS, we controllably tune the Young's modulus of the samples to span over an order of magnitude. The measured results are in good agreement with those obtained using a conventional load-frame system. Our fiber-based polarimetric stress sensor shows promise for use as a simple research tool that is portable and suitable for a wide variety of applications.