Computational adaptive optics for polarization-sensitive optical coherence tomography

Abstract

Defocus aberration in optical systems, including optical coherence tomography (OCT) systems employing Gaussian illumination, gives rise to the well-known compromise between transverse resolution and depth-of-field. This results in blurry images when out-of-focus, whilst other low-order aberrations (e.g., astigmatism, coma, etc.) present in both the OCT system and biological samples further reduce image resolution and contrast. Computational adaptive optics (CAO) is a computed optical interferometric imaging technique that modifies the phase of the OCT data in the spatial frequency domain to correct optical aberrations and provide improvement of the image quality throughout the three-dimensional (3D) volume. In this Letter, we report the first implementation of CAO for polarization-sensitive OCT to correct defocus and other low-order aberrations, providing enhanced polarization-sensitive imaging contrast (i.e., intensity and phase retardation) on a 3D OCT phantom, molded plastics, ex vivo chicken breast tissue, and ex vivo human breast cancer tissue.

Computational refocusing of Jones matrix polarization-sensitive optical coherence tomography and investigation of defocus-induced polarization artifacts

“…Our method uses the JM-OCT principle. The advantage of JM-OCT over the CPL-PSOCT [ 32 ], which was used for the polarization sensitive (PS-) ISAM [ 31 ] and PS-CAO [ 33 ], is that it can provide birefringence, i.e., local phase retardation through local Jones matrix analysis [ 50 ]. The disadvantage of JM-OCT is that it requires phase information to compute both the cumulative and local phase retardations.…”

“…In contrast, the cumulative phase retardation measurement of CPL-PSOCT is phase insensitive. Therefore, its combination with computational refocusing, i.e., PS-ISAM [ 31 ] and PS-CAO [ 33 ], might be more robust than our computational-refocusing JM-OCT. The disadvantage of CPL-PSOCT is that the phase-insensitive method only provides the cumulative phase retardation and gives neither local phase retardation nor optic axis orientation.…”

“…In their method, they combined ISAM and circularly-polarized light based PS-OCT (CPL-PSOCT) [ 32 ], and demonstrated cumulative phase retardation imaging with computational refocusing. Similarly, Wang et al demonstrated the combination of computational adaptive optics (CAO) with the CPL-PSOCT [ 33 ]. CPL-PSOCT is particularly suitable for computational refocusing because it uses only the intensity information to compute the cumulative phase retardation.…”

Advances in Optical Coherence Tomography Imaging Technology and Techniques for Choroidal and Retinal Disorders

“…A stretched-pulse mode-locked laser light source was tested to increase the A-scan rate and combat the adverse effects of eye movement [ 53 ]. Boppart et al established the first model of CAO in polarization-sensitive OCT (PS-OCT), which corrects low-order aberrations in ex vivo human tissues [ 54 ]. There have also been proposed advances in improving CAO aberration correction capabilities and image quality [ 55 ].…”

Geometrically accurate real-time volumetric visualization of the middle ear using optical coherence tomography

“…Geometric distortion along the edges of the FOV arises due to the difficulty in correctly segmenting calibration grid points in the presence of optical astigmatism. Methods for correcting astigmatism in OCT volumes have previously been reported[49][50][51] and their combination with the techniques of this study could potentially improve image accuracy at the edges of the FOV. Accuracy was also low in the central few pixels of our image due to mirror bandwidth limitation and central artefacts from internal reflections in our handpiece optics.…”