Fiber-based polarization-sensitive OCT of the human retina with correction of system polarization distortions

Abstract

In polarization-sensitive optical coherence tomography (PS-OCT) the use of single-mode fibers causes unpredictable polarization distortions which can result in increased noise levels and erroneous changes in calculated polarization parameters. In the current paper this problem is addressed by a new Jones matrix analysis method that measures and corrects system polarization distortions as a function of wavenumber by spectral analysis of the sample surface polarization state and deeper located birefringent tissue structures. This method was implemented on a passive-component depth-multiplexed swept-source PS-OCT system at 1040 nm which was theoretically modeled using Jones matrix calculus. High-resolution B-scan images are presented of the double-pass phase retardation, diattenuation, and relative optic axis orientation to show the benefits of the new analysis method for in vivo imaging of the human retina. The correction of system polarization distortions yielded reduced phase retardation noise, and better estimates of the diattenuation and the relative optic axis orientation in weakly birefringent tissues. The clinical potential of the system is shown by en face visualization of the phase retardation and optic axis orientation of the retinal nerve fiber layer in a healthy volunteer and a glaucoma patient with nerve fiber loss.

Estimation of Jones matrix, birefringence and entropy using Cloude-Pottier decomposition in polarization-sensitive optical coherence tomography

“…Among them, Makita et al raised one of the fundamental issues in PS-OCT that the mean of the phase retardation is significantly biased from the true value because of asymmetric distribution [10]. Various methods have been developed to apply averaging to such polarimetric parameters [11][12][13][14][15][16][17][18][19]. In another approach, an estimator of the phase retardation based on the likelihood of the distribution was also developed [20].…”

Polarization Sensitive Optical Coherence Tomography: A Review of Technology and Applications

“…By multiplexing two different states using a passive polarization delay unit as shown in Figure 4d, the four elements of a Jones matrix can be measured simultaneously [18,73,74]. In that case, the sample beam is split into two orthogonal input Jones vectors which travel different path lengths in the sample arm and therefore generate signals at different depths in the OCT image.…”

“…An extreme case of a diattenuating element with p 1 = 1 and p 2 = 0 is a linear polarizer which only transmits light along axis 1. It should be noted that diattenuation in biological tissue is usually very weak and thus is often assumed negligible for PS-OCT [16,17], although attempts have been made to quantify diattenuation using PS-OCT [15,17,18]. …”

“…Since OCT is based on broadband light covering a wide range of wavelengths, efforts have been made to mitigate effects such as polarization mode dispersion in PS-OCT systems based on optical fibers [18,[27][28][29][30].…”

Polarization sensitive optical coherence tomography utilizing a buffered swept source laser

“…While conventional OCT detects the reflectivity of scattering layers, the measurement of polarization dependent effects in tissue, like birefringence and depolarization, requires an extended setup [1]. Several concepts have proved capability, but most common PS-OCT systems are characterized by a high complexity due to numerous additional components for polarization adjustment, maintenance and detection [2,3]. Since fast tunable lasers [4] are available, the temporally resolved detection of interference spectra for frequency domain imaging has become the preferred choice for high speed OCT concepts.…”