Advanced multi-contrast Jones matrix optical coherence tomography for Doppler and polarization sensitive imaging

Abstract

An advanced version of Jones matrix optical coherence tomography (JMT) is demonstrated for Doppler and polarization sensitive imaging of the posterior eye. JMT is capable of providing localized flow tomography by Doppler detection and investigating the birefringence property of tissue through a three-dimensional (3-D) Jones matrix measurement. Owing to an incident polarization multiplexing scheme based on passive optical components, this system is stable, safe in a clinical environment, and cost effective. Since the properties of this version of JMT provide intrinsic compensation for system imperfection, the system is easy to calibrate. Compared with the previous version of JMT, this advanced JMT achieves a sufficiently long depth measurement range for clinical cases of posterior eye disease. Furthermore, a fine spectral shift compensation method based on the cross-correlation of calibration signals was devised for stabilizing the phase of OCT, which enables a high sensitivity Doppler OCT measurement. In addition, a new theory of JMT which integrates the Jones matrix measurement, Doppler measurement, and scattering measurement is presented. This theory enables a sensitivity-enhanced scattering OCT and high-sensitivity Doppler OCT. These new features enable the application of this system to clinical cases. A healthy subject and a geographic atrophy patient were measured in vivo, and simultaneous imaging of choroidal vasculature and birefringence structures are demonstrated.

Optically buffered Jones-matrix-based multifunctional optical coherence tomography with polarization mode dispersion correction

“…Each spectral interference signal is sampled with 2,368 points, which corresponds to a wavelength range of 104 nm. Spectral shifts among the spectra, which are due to timing jitter in the Atrigger, are estimated and corrected by use of the calibration signal [28]. The sampled interference signals are numerically rescaled to be linear in the wave-number using predefined rescaling parameters determined by a time-frequency calibration method [39].…”

“…The signal roll-off can cause different signal strengths between two OCT signals corresponding to the two incident polarization states. This signal roll-off is not corrected in our method, since the effect of signal roll-off to the polarization measurement is not significant as far as the roll-off speed is similar for the both incident polarizations as discussed in Section 5.4 of [28]. Although it was not implemented in our system, additional numerical correction of the signal roll-off [36] would further enhance the accuracy of polarization measurement.…”

“…Hence, the four entries of the Jones matrix can be properly demultiplexed [28], and the spectrum of a raw measured Jones matrix is obtained as…”

“…The source arm is equipped with an optical buffering module built with a fast optical switch (FOS), which is similar to that demonstrated by Dhalla et al [32]. Aside from the buffering module, it is nearly identical to a JM-OCT system that we have previously demonstrated [28].…”

“…Recently, we demonstrated Jones-matrix-based multifunctional OCT (JM-OCT) [27,28]. This system simultaneously measures OCT, Doppler shift, and the polarization properties of a sample, and it enables simultaneous imaging of tissue structure, vasculature, and birefringent tissue.…”