Novel input polarisation independent endoscopic cross‐polarised optical coherence tomography probe

Abstract

Lead by the original idea to perform noninvasive optical biopsies of various tissues, optical coherence tomography found numerous medical applications within the last two decades. The interference based imaging technique opens the possibility to visualise subcellular morphology up to an imaging depth of 3 mm and up to micron level axial and lateral resolution. The birefringence properties of the tissue are visualised with enhanced contrast using polarisation sensitive or cross-polarised optical coherence tomography (OCT) techniques. Although, it requires strict control over the polarisation states, resulting in several polarisation controlling elements. In this work, we propose a novel input-polarisation independent endoscopic system based on cross-polarised OCT. We tested the feasibility of our approach by measuring the polarisation change from a quarter-wave plate for different rotational angles. Further performance tests reveal a lateral resolution of 30 μm and a sensitivity of 103 dB. Images of the human nail bed and cow muscle tissue demonstrate the potential of the system to measure structural and birefringence properties of the tissue endoscopically.

A Proposal to Perform High Contrast Imaging of Human Palatine Tonsil with Cross Polarized Optical Coherence Tomography

“…In the future, this technique can be combined with highresolution OCT systems to achieve cellular resolution and improved contrast. Endoscopic implementation [32,33] of the same would allow imaging epithelial layer morphology within the crypts which would increase the clinical value of the technique in diseases such as tonsillar cancer and recurrent tonsillitis.…”

Depth encoded cross-polarized optical coherence tomography with polarization maintaining fiber

“…PS-OCT measures the changes in the polarization state of light by analyzing the difference between images obtained from two orthogonally polarized light components [2][3]. CP-OCT, instead, provides two contrast distributions, in the following named co-and cross-polarized images [4][5]. The tissues can change the polarization state of the probing light beam due to birefringence, diattenuation, and depolarization of scattered light.…”

Polarization Independent Optical Coherence Tomography

“…The acquired images can be combined to eliminate the polarization-dependent artifacts. Similarly, CP-OCT systems [23][24][25][26][27], acquire two images of the sample, one for which the signal reflected from the sample has the same polarization as the illumination polarization and another for which the reflected signal polarization is orthogonal. Unlike PS-OCT which requires circular polarization for the sample illumination, the polarization of the sample illumination in CP-OCT can be any [24,28,29].…”