Conical scan polarization-sensitive optical coherence tomography

Abstract

We report on a new articular cartilage imaging technique with potential for clinical arthroscopic use, by supplementing the variable-incidence-angle polarization-sensitive optical coherence tomography method previously developed by us with a conical beam scan protocol. The technique is validated on bovine tendon by comparing experimental data with simulated data generated using the extended Jones matrix calculus. A unique capability of this new optical technique is that it can locate the "brushing direction" of collagen fibers in articular cartilage, which is structural information that extends beyond established methods such as split-line photography or birefringent fast-axis measurement in that it is uniquely defined over the full azimuthal-angle range of (-π, + π). The mapping of this direction over the cartilage surface may offer insights into the optimal design of tissue-engineering scaffolds for cartilage repair.

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

“…Since this region corresponds to the corneoscleral limbus, where the corneal and scleral laminar tissues change transitionally with fibrovascular ridges [60,61], the anisotropic fibrous structure might have anisotropic optic axes in the kernel window and have resulted in the high entropy. It is known that such anisotropic fibrous structure can be found at various biological tissues [62][63][64]. Since the entropy is sensitive to both the phase retardation and the optic axis, the entropy is effective to find any type of anisotropic birefringence except for a special case with a combination of diattenuation and depolarization [65].…”

“…As shown in the corneoscleral limbus, the visualization of both the local retardation and the entropy was important to characterize the tissue. In addition, the optic axis imaging will provide more comprehensive understanding of the tissue birefringence [62][63][64], and remains for future studies. …”

Use of combined polarization-sensitive optical coherence tomography and Mueller matrix imaging for the polarimetric characterization of excised biological tissue

“…This is also shown in the PS-OCT and corroborated in other work involving axis orientation and retardance. 60 The PS-OCT images of retardation show the typical oscillatory pattern, as the other bovine tendon samples. Local retardation was ultimately calculated with the algorithm by Jiao et al 40 and proposed by others.…”

Fiber-optic polarization diversity detection for rotary probe optical coherence tomography

“…However, being a Michelson OCT interferometer, this type of probe has less sensitivity relative to Mach-Zehnder interferometers [11]. An alternative approach to compensate for polarization effects in rotating probes is to use a polarization diversity detection (PDD) scheme [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. In this scheme, polarization beam splitters (PBSs) are used following the sample/reference combiner to separate the interference signal into its orthogonal (X and Y) polarizations.…”

“…However, this type of setup is costly, difficult to miniaturize, and cumbersome since it involves the alignment of multiple beam splitters and collimators. Fiber-based PDD schemes are also reported using unbalanced receivers [21][22][23][24] and balanced receivers with 50∕50 SM fiber couplers [25] and 50∕50 polarization maintaining (PM) fiber couplers [26][27][28]. Systems with unbalanced receivers have less signal-to-noise ratio compared to systems with balanced receivers because of a lower detector dynamic range [11].…”