Fundamentals of a metal surface imaging system based on laser-optic principles

Bektaş, Murat
The confocal laser-scanning microscope (CLSM), known simply as a confocal microscope, is an important instrument which allows us to observe an object or a surface in three-dimensions with confocal microcopy technique. The basic difference of confocal microscopy is detecting the in- focused light, while the out of focus light is blocked out by the help of a pinhole. By this optical dissection ability of confocal microcopy, CLSM provides the images of investigated object or the surface with higher resolution and contrast as against conventional microscopic systems. Various types of Laser Scanning confocal microscopes have been developed and due to its high resolution and contrast they have become an invaluable tool for investigations in many areas like biology and medicine. In addition to its wide range of use, confocal microscope can be used for detecting of possible defects on metal surfaces. In this thesis our goal was to develop the analytical and theoretical back ground necessary for the successful completion of a laser/optic system coupled to a fiber bundle waveguide based on confocal scanning principles to effectively image a non-uniform, metal surface with speed and precision in order to assess any surface damage. In addition to this analysis we demonstrate a working confocal microscopy set-up and investigate the factors which affect the image quality by the experiments conducted in METU (Middle East Technical University) Laser Laboratory.


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Qasrawi, A. F.; Hasanlı, Nızamı (IOP Publishing, 2007-09-01)
The structural and optical properties of Bridgman method grown Tl2InGaSe4 crystals have been investigated by means of room temperature x-ray diffraction, and transmittance and reflectance spectral analysis, respectively. The x-ray diffraction technique has shown that Tl2InGaSe4 is a single phase crystal of a monoclinic unit cell that exhibits the lattice parameters of a = 0.77244 nm, b = 0.64945 nm, c = 0.92205 nm and beta = 95.03 degrees . The optical data have revealed an indirect allowed transition band ...
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This paper discusses the bit-error-rate (BER) performance of an aeronautical uplink optical wireless communication system (OWCS) when a Gaussian beam is employed and the M-ary pulse position modulation technique is used in an atmospheric turbulent medium. Weak turbulence conditions and log-normal distribution are utilized. The Gaussian beam is assumed to propagate on a slant path, the transmitter being ground-based, and the airborne receiver is on-axis positioned. Variations of BER are obtained against the ...
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Diffractive lenses, such as Fresnel zone plates, photon sieves, and their modified versions, have been of significant recent interest in high-resolution imaging applications. As the advent of diffractive lens systems with different configurations expands, the fast and accurate simulation of these systems becomes crucial for both the design and image reconstruction tasks. Here we present a fast and accurate method for computing the 2D point-spread function (PSF) of an arbitrary diffractive lens. The method i...
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The absorption of whistler waves in a magnetized cylindrical plasma due to coupling with oblique Langmuir waves is investigated. Two types of mechanisms exist for whistler absorption. The first one is related to the excitation of Langmuir waves in the volume of the dense plasma and their subsequent absorption due to the electron collisions. The second one is the emission of Langmuir waves outside of the cylindrical plasma when it is surrounded by the rare plasma. The relation between these whistler absorpti...
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In this paper, we report a metamaterial absorber design that achieves a broad absorption band encompassing the whole long-wavelength infrared (LWIR) region. The structure consists of two parallel metasurfaces buried in an amorphous silicon dielectric layer, where the minimum size for all possible planar details does not go below 1 mu m, making the use of standard optical lithography possible for fabrication. The dielectric layer of the structure is placed over a metallic ground plane that inhibits the trans...
Citation Formats
M. Bektaş, “Fundamentals of a metal surface imaging system based on laser-optic principles,” M.S. - Master of Science, Middle East Technical University, 2009.