Real-time fiber-based multi-functional spectral-domain optical coherence tomography at 13 µm

Abstract

We demonstrate a high-speed multi-functional spectral-domain optical coherence tomography system, using a broadband light source centered at 1.3 microm and two InGaAs line scan cameras capable of acquiring individual axial scans in 24.4 micros, at a rate of 18,500 axial scans per second. Fundamental limitations on the accuracy of phase determination as functions of signal-to-noise ratio and lateral scan speed are presented and their relative contributions are compared. The consequences of phase accuracy are discussed for both Doppler and polarization-sensitive OCT measurements. A birefringence artifact and a calibration procedure to remove this artifact are explained. Images of a chicken breast tissue sample acquired with the system were compared to those taken with a time-domain OCT system for birefringence measurement verification. The ability of the system to image pulsatile flow in the dermis and to perform functional imaging of large volumes demonstrates the clinical potential of multifunctional spectral-domain OCT.

Doppler Optical Coherence Tomography

“…Phase fluctuations are mainly attributable to two factors (Park et al., 2005): a signal-to-noise ratio (SNR) dependent term and a term that depends on the lateral sampling. If lateral oversampling is increased it may therefore be possible to hit the boundary set by SNR of the OCT system.…”

Three-dimensional optical coherence elastography by phase-sensitive comparison of C-scans

“…Although this sampling results in additional phase noise, it is a convenient means of ensuring sufficiently small y-direction offsets between scans to enable effective phase-sensitive detection. 43 The B-scan acquisition (indicated by "x-scanning" in Fig. 1) was synchronized with the mechanical loading [Figs.…”

Polarization Sensitive Optical Coherence Tomography: A Review of Technology and Applications

“…By computing this angle between the Stokes vectors at the sample surface and those within the tissue, cumulative phase retardation can be computed at any sample position [66,67]. Furthermore, the direction of the optic axis can be determined from rotations of the pair of perpendicular Stokes vectors on the Poincaré sphere [68]. In such dual-input PS-OCT systems, polarization parameters such as retardation, axis orientation, and diattenuation can also be assessed using the Jones formalism.…”

“…The advent of Fourier domain OCT (or: frequency domain OCT), which computes A-scan signals by a Fourier transform of the interference spectrum, provided a huge increase in detection sensitivity and the possibility to scan even faster since no more mechanical reference mirror movement was required to perform depth scanning [5,[81][82][83]. First high-speed PS-OCT systems with spectrometer-based detection provided scan rates of several tens of A-scans per second [41,68]. These spectral domain (SD) PS-OCT prototypes employed two spectrometer cameras, one for each orthogonal polarization channel.…”

“…Further, PS-OCT has been used for qualitative imaging mostly; the exploitation of quantitative measurements however bears great potential for diagnostics and other applications, as will be demonstrated in the next sections. PS-OCT was also combined with other functional OCT extensions such as Doppler OCT or OCT angiography [30,68,80,[103][104][105]. Such combinations may not only improve the contrast for vascular tissue components but also provide additional, complementary insight into disease patterns [30,103,105,106].…”