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Optical coherence tomography (OCT) is a non-invasive imaging technique invented in 1991 and allowing
the observation of biological tissues with millimeter depth of penetration and a few micrometer resolution. In the
standard time-domain OCT setup (TD-OCT), a broadband light source is used with a Michelson interferometer
where one of the mirrors is replaced by the sample (which is mechanically moved transversally during data
acquisition) while the other is axially vibrating. By analyzing the temporal signal at the exit of the interferometer, a
high resolution tomographic cut of the sample can be obtained. A number of new OCT setups have been proposed
since 1991 in order to improve the data acquisition speed. In particular, Fourier-domain OCT (FD-OCT) has allowed
in vivo observation of samples by eliminating the necessity of the axial motion of the reference mirror in the setup.
We propose in this paper new OCT setups having the same potential without requiring numerical treatment of the
signal (as it is the case in FD-OCT). Because those setups are such that the axial information of the sample becomes
linearly distributed at different points of space in an interference pattern, we call them spatial-domain OCT setups
(SD-OCT). SD-OCT setups use a tilted mirror in a Michelson interferometer to produce an interference pattern
which is imaged on a CCD detector. The pattern contains all the information on the sample and is obtained without
mechanical motion or numerical treatment of the recorded signal. In order to validate the proposed scheme,
prototypes of the setups have been made in the laboratories of COPL at Laval University; biological samples such as
onion peels and phloem of trees have been tested in order to produce their tomographic images. Comparisons of
some of our results with those from a commercial setup with the same samples had notably confirmed the capacity
of ours prototypes to effectively image biological samples.
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