Double common-path interferometer for flexible optical probe of optical coherence tomography

Abstract

A flexible curled optical cord is useful for a common-path optical coherence tomography (OCT) system because a bending-insensitive arbitrary length can be chosen for the endoscopic imaging probe. However, there has been a critical problem that the partial reflector needs to be placed in between the sample and the objective lens. It limits the structure design of optical probe and leads to a low transverse resolution OCT imaging. Instead of a conventional single common-path interferometer, we propose a novel double common-path interferometer configuration in order to generate an interference signal that is independent of the optical distance between the partial reflector and sample. Due to the limitless tuning of the objective distance, an objective lens with a high numerical aperture (NA) up to 0.85 can be successfully used for phase-sensitive optical coherence tomography to achieve a 3-dimensional profile image of a transverse resolution of 0.7 μm. The intensity and phase terms of the interference signal can be obtained simultaneously from a Fourier-domain mode locked swept laser source for fast data acquisition with a phase stability of 979 pm.

Double Interferometer Design for Independent Wavefront Manipulation in Spectral Domain Optical Coherence Tomography

“…Previous works provided detailed analysis of the double interferometer OCT design for common path systems 36–39 . The design was shown to effectively mimic a conventional single interferometer system in case that the optical path length difference at one interferometer compensates the path length difference at the other one 35–40 .…”

A bimodal endoscopic imager in a glass package

“…Endomicroscopy, performing functional microscopy using endoscopic imaging systems, is a thriving field with the clear vision of replacing traditional biopsy in the near future. Numerous imaging techniques, such as endocytoscopy and flu orescence imaging, are already in routine clinical use; others, such as confocal laser endomicroscopy [1], Raman spectr oscopy [2] or optical coherence tomography (OCT) [3,4], are expected to enter routine clinical use in the imminent future. Regardless of the target pathology, however, these optical methods are yet to attain the selectivity and specificity of traditional biopsy when implemented individually.…”