Double diversity optical coherence tomography

Abstract

ABSTRACT This article provides theoretical analysis for a new generation of optical coherence tomography (OCT) scanners to overcome some main limitations of the technology. In the new design, exposure and detection are not limited to plane-waves that enter or reflect back from the sample exclusively orthogonally. Instead, the sample is scanned by more complex radiation patterns such as spherical or partially spherical light waves. Images that are generated based on this data acquisition strategy can reveal some structural features of the sample that usually remain hidden in conventional OCT imaging. Coherence tomography is based on wide-band reflectometry. Therefore, wavelength diversity is an essential element of technology. The proposed system adds a second form of diversity to the conventional OCT design, which is the angle of incidence for exposure and detection. Since the exposing beam is not necessarily orthogonal to the sample's surface, the propagation wave-vector of the beam has a component in the transverse plane. The amplitude and direction of this transverse component is the second diversity dimension added to the new design. Here, the forward problem is formulated for the most general case, and an efficient image reconstruction algorithm is offered based on the theory of singular value decomposition in continuous space. It is proved mathematically that at the limit, when the amplitude of the transverse component of the wave-vector approaches zero, the formulation of the forward and inverse problems converge to the case of conventional OCT.