High-resolution optical coherence tomography over a large depth range with an axicon lens

Abstract

In optical coherence tomography, axial and lateral resolutions are determined by the source coherence length and the numerical aperture of the sampling lens, respectively. Whereas axial resolution can be improved by use of a broadband light source, there is a trade-off between lateral resolution and focusing depth when conventional optical elements are used. We report on the incorporation of an axicon lens into the sample arm of an interferometer to overcome this limitation. Using an axicon lens with a top angle of 160 degrees , we maintained 10-microm or better lateral resolution over a focusing depth of at least 6 mm. In addition to having high lateral resolution, the focusing spot has an intensity that is approximately constant over a greater depth range than when a conventional lens is used.

Determination of Melanoma Lateral and Depth Margins: Potential for Treatment Planning and Five-Year Survival Rate

“…¶ Lateral resolution can be 10 μm or better, axial resolution varies from 10 to 20 μm (Ding et al, 2002;Schenk & Brezinski, 2002). δ Axial resolution varies from 1 to 1.9 μm (Campagnola et al, 2002;Moreaux et al, 2000).…”

Deconvolution methods for mitigation of transverse blurring in optical coherence tomography

“…These algorithms are designed for a single axial scan only and do not incorporate information as defined by the Gaussian optics model. Experimental setups have utilized additional optical hardware such as adaptive optics or axicon lenses to increase the transverse resolution over large depths in the specimen [20], [21]. Dynamic focusing techniques have been implemented for OCT and optical coherence microscopy to generate images with high transverse resolutions over relatively large depths, which can be useful for en face imaging [4], [22].…”

“…Next, the truncated SVD (TSVD) is used to provide a regularized solution (21) where is determined by a regularization parameter, , which is a corresponding threshold such that all are retained [29]. This method is chosen because it reduces the emphasis on smaller singular values in the minimum norm solution, which are more correlated to the noise.…”

High-performance axicon lenses based on high-contrast, multilayer gratings

“…1,2 These unique properties have made axicons useful in many applications in biological imaging, such as optical coherence tomography 3,4 and light-sheet microscopy, 5 where the linear focusing and robustness of Bessel-like beams to scattering enable improvements in resolution and depth of field. They are also used in telescopes that require the simultaneous focusing of targets located at different depths.…”