title: Quantifying the influence of Bessel beams on image quality in optical coherence tomography.
abstract: Light scattered by turbid tissue is known to degrade optical coherence tomography (OCT) image contrast progressively with depth. Bessel beams have been proposed as an alternative to Gaussian beams to image deeper into turbid tissue. However, studies of turbid tissue comparing the image quality for different beam types are lacking. We present such a study, using numerically simulated beams and experimental OCT images formed by Bessel or Gaussian beams illuminating phantoms with optical properties spanning a range typical of soft tissue. We demonstrate that, for a given scattering parameter, the higher the scattering anisotropy the lower the OCT contrast, regardless of the beam type. When focusing both beams at the same depth in the sample, we show that, at focus and for equal input power and resolution, imaging with the Gaussian beam suffers less reduction of contrast. This suggests that, whilst Bessel beams offer extended depth of field in a single depth scan, for low numerical aperture (NA < 0.1) and typical soft tissue properties (scattering coefficient, μs = 3.7 mm(-1) and high scattering anisotropy, g > 0.95), superior contrast (by up to ~40%) may be obtained over an extended depth range by a Gaussian beam combined with dynamic focusing.
authors.affiliation: Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
authors.forename: Andrea
authors.initials: A
authors.lastname: Curatolo
authors.affiliation: Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.|Centre for Microscopy, Characterisation &Analysis, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
authors.forename: Peter R T
authors.initials: PRT
authors.lastname: Munro
authors.affiliation: Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
authors.forename: Dirk
authors.initials: D
authors.lastname: Lorenser
authors.affiliation: Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
authors.forename: Parvathy
authors.initials: P
authors.lastname: Sreekumar
authors.affiliation: Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
authors.forename: C Christian
authors.initials: CC
authors.lastname: Singe
authors.affiliation: Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
authors.forename: Brendan F
authors.initials: BF
authors.lastname: Kennedy
authors.affiliation: Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic &Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.|Centre for Microscopy, Characterisation &Analysis, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
authors.forename: David D
authors.initials: DD
authors.lastname: Sampson