Measurement and imaging of birefringent axis by phase resolved polarization sensitive optical coherence tomography

Abstract

We present a modified method of polarization sensitive optical coherence tomography (PS-OCT) that measures backscattered intensity, birefringence, and fast optic axis orientation with only one single A-scan per transverse measurement location. The technique employs a standard two-channel PS-OCT setup in combination with a phase sensitive recording of the interferometric signals in the two orthogonally polarized detection channels. We use a Hilbert transform based algorithm to extract amplitude and phase information contained in the interferometric signals. While the birefringence information is obtained from the signal amplitudes, as usual in PS-OCT, a careful analysis of the propagating beams by the Jones calculus reveals, that the information on the fast axis orientation is encoded entirely in the phase difference of the interferometric signals. We demonstrate our method and report on accuracy and precision of birefringence and fast axis measurements in a transparent technical object. Finally, we present PS-OCT maps of birefringence and of fast axis orientation recorded in scattering tissue.