Transversal ultrahigh-resolution polarizationsensitive optical coherence tomography for strain mapping in materials.

Optical coherence tomography (OCT) and its extension, polarization-sensitive (PS-)OCT, are techniques for contactless and nondestructive imaging of internal structures. In this work, we apply PS-OCT for material characterization. We use a transversal scanning, ultra-high resolution (UHR-)PS-OCT setup providing cross-sectional as well as inplane information about the internal microstructure, the birefringence and the orientation of the optical axis within the material. We perform structural analysis and strain-mapping for different samples: we show the necessity of UHR imaging for a highly strained elastomer sample, and we discuss the effect of large birefringence on the PS-OCT images. Furthermore, we investigate high-aspect ratio photoresist moulds for the production of microelectromechanical parts (MEMS), demonstrating that transversal UHR-PSOCT is a promising tool for non-destructive strain-mapping.

Measurement and imaging of birefringence and optic axis orientation by phase resolved polarization sensitive optical coherence tomography.

We present an improved method of polarization sensitive optical coherence tomography that enables measurement and imaging of backscattered intensity, birefringence, and fast optic axis orientation simultaneously with only one single A-scan per transverse measurement location. While intensity and birefringence data are obtained in a conventional way, the optic axis orientation is determined from the phase difference recorded in two orthogonal polarization channels. We report on accuracy and precision of the method by measuring birefringence and optic axis orientation of well defined polarization states in a technical object and present maps of birefringence and, what we believe for the first time, of optic axis orientation in biological tissue.