Abstract:
The objective of this research is to design and construct an optical
coherence tomography (OCT) system, beside the comparison of the
efficiency of this system with other tomography systems, like
Photoacoustic system and Raman spectrometer, to evaluate its
operation.
Michelson interferometer was designed; which represent the heart of the
system, which consist of two mirrors, beam splitter to transmitt 50% of
the incident light and reflect the other half. Three types of laser sources
were used, helium neon with wavelength 632.8 nm and 4mW, diode
lasers with two wavelengths (700 nm and 1550 nm), power ≤4.25mW.
Performance of the constructed system was completed by
receiving the interference fringes by the detector, which was connected
to the display unit.
Digital oscilloscope, with high mathematical functions, was used
to display signal information in frequency domain. From the
experiments results we noticed that Fourier transformation (FT) was the
best mathematical function, which can be used with the constructed
(OCT) system.
Also CCD camera was used with the system to give two & three
dimensional images for the studied samples.
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The constructed system can be used for many purposes, for
examples: measurement of the thickness and determination of optical
properties for different samples.
The samples studied by the constructed OCT system were: glass slides,
polymer\ pyrex\ carbon coating, layers of onion and cancer skin.
The results were represented in tables, figures and images.
To prove the good performance of the constructed OCT system
the results were compared with another results gained by a
Photoacoustic system for the same samples. Beside that FT Raman
spectroscopy was used also to differentiate between normal and
abnormal tissue.
The comparisons showed that the three tomographic systems can
be used as diagnostic systems with high resolution. Also all
tomographic systems have no ionizing effect compared with another
tomography imaging (nuclear rays).
The comparison proved that the constructed OCT system is operated
efficiently and correctly.
