A spectral-domain Optical Coherence Tomography (OCT) surface profilometry prototype has been developed for the
purpose of surface metrology of optical elements. The prototype consists of a light source, spectral interferometer,
sample fixture and software currently running on Microsoft® Windows platforms. In this system, a broadband light
emitting diode beam is focused into a Michelson interferometer with a plane mirror as its sample fixture. At the
interferometer output, spectral interferograms of broadband sources were measured using a Czerny-Turner mount
monochromator with a 2048-element complementary metal oxide semiconductor linear array as the detector. The
software performs importation and interpolation of interferometer spectra to pre-condition the data for image
computation. One dimensional axial OCT images were computed by Fourier transformation of the measured spectra. A
first reflection surface profilometry (FRSP) algorithm was then formulated to perform imaging of step-function-surfaced
samples. The algorithm re-constructs two dimensional colour-scaled slice images by concatenation of 21 and 13 axial
scans to form a 10 mm and 3.0 mm slice respectively. Measured spectral interferograms, computed interference fringe
signals and depth reflectivity profiles were comparable to simulations and correlated to displacements of a single
reflector linearly translated about the arm null-mismatch point. Surface profile images of a double-step-function-surfaced
sample, embedded with inclination and crack detail were plotted with an axial resolution of 11 μm. The surface shape,
defects and misalignment relative to the incident beam were detected to the order of a micron, confirming high resolution
of the developed system as compared to electro-mechanical surface profilometry techniques.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.