Share Email Print
cover

Proceedings Paper

Dynamic coherent focus for transversal resolution enhancement of OCT
Author(s): Franz Lexer; Adolf Friedrich Fercher; Harald Sattmann; Wolfgang Drexler; Sergej Molebny
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

One of the major problems of optical coherence tomography (OCT) is limited transversal resolution. A small focus can certainly be generated using a small confocal beam parameter. But then transversal resolution becomes severely dependent on the position of the beam focus within the object. Hence to achieve optimal transversal resolution within the whole object, the focus of the illuminating beam has to be shifted during the coherence scan throughout the object depth. To maintain coherence the optical path length of the reference beam has to be shifted by the same amount. In our experimental setup we use an optical design which makes it possible to shift the focus of the measurement beam without changing the optical path length of the reference beam. We call this technique dynamic coherent focus because a focus is created that remains coherent to the reference beam during the whole coherence scan. Using a Ronchi ruling resolution target with 200 line pairs/mm we demonstrate that the transversal resolution is better than 5 micrometer. In the cross sectional image of a human cornea in vitro epithelium and the endothelium layers are visible with a longitudinal resolution of approximately 14 micrometer and transversal resolution of better than 5 micrometers. The cellular structure of the endothelium is resolved.

Paper Details

Date Published: 24 April 1998
PDF: 6 pages
Proc. SPIE 3251, Coherence Domain Optical Methods in Biomedical Science and Clinical Applications II, (24 April 1998); doi: 10.1117/12.306043
Show Author Affiliations
Franz Lexer, Institute of Medical Physics/Univ. of Vienna (Austria)
Adolf Friedrich Fercher, Institute of Medical Physics/Univ. of Vienna (Austria)
Harald Sattmann, Institute of Medical Physics/Univ. of Vienna (Austria)
Wolfgang Drexler, Institute of Medical Physics/Univ. of Vienna (Austria)
Sergej Molebny, Institute of Medical Physics/Univ. of Vienna (Austria)


Published in SPIE Proceedings Vol. 3251:
Coherence Domain Optical Methods in Biomedical Science and Clinical Applications II
Valery V. Tuchin; Joseph A. Izatt, Editor(s)

© SPIE. Terms of Use
Back to Top