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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
631

Computation of the Optical Point Spread Function of a Ball Lens

Lien, Chun-Yu 24 September 2012 (has links)
In this thesis, we analyze the simplest optical imaging system: a ball lens. The traditional method of using a geometric optics analysis on an optical system only gives the roughest qualitative solution due to the lack of consideration of wave properties. Therefore, for accurate quantitative results, we need to analyze said system with a complete wave theory approach. The reason that we chose a ball lens as the focus of this research is due to its spherical symmetry properties which allows us to rigorously investigate it with different analytic methods. We will apply geometric optics, Fourier optics, scalar wave optics, and electromagnetic optics methods to compute the point spread functions (PSF) of a ball lens under the assumption that the point source is isotropic. We will follow up by predicting the spot sizes that correspond to each mean. First, with geometric optics (GO), we apply the analytic ray tracing method to correlate the origins of light rays passing through the ball lens to their respective positions on the receptive end. We can then evaluate the energy distribution function by gathering the density of rays on image plane. Second, in the theory of Fourier optics (FO), to obtain the analytic formula of the point spread function, the integral kernel can be approximated as the Fresnel integral kernel by means of paraxial approximation. Compared to GO, the results from FO are superior due to the inclusion of wave characteristics. Furthermore, we consider scalar wave optics by directly solving the inhomogeneous Helmholtz equation which the scalar light field should satisfy. However, the light field is not assigned to an exact physical meaning in the theory of scalar wave optics, so we reasonably require boundary conditions where the light field function and its first derivative are continuous everywhere on the surface of ball lens. Finally, in the theory of electromagnetic optics (EMO), we consider the polarization of the point source, and the two kinds of Hertz vectors and , both of which satisfy inhomogeneous Helmholtz equation, and are derived from Maxwell¡¦s equations in spherical structures. In contrast with the scalar wave optics, the two Hertz vectors are defined concretely thus allowing us to assign exact boundary conditions on the interface. Then the fields corresponding to and are averaged as the final point spread function.
632

Study of microfluidic measurement techniques using novel optical imaging diagnostics

Park, Jaesung 25 April 2007 (has links)
Novel microscale velocity and temperature measurement techniques were studied based on confocal laser scanning microscopy (CLSM) and optical serial sectioning microscopy (OSSM). Two microscopic measurement systems were developed, 1) a CLSM micro particle image velocimetry (PIV) system with a dual Nipkow disk confocal unit (CSU-10), a CW argon-ion laser and an upright microscope, and 2) an OSSM micro- particle tracking velocimetry (PTV) system with an epi-fluorescence microscope and a non-designed specimen to make a three-dimensional (3-D) diffraction particle image. The CLSM micro-PIV system shows a unique optical slicing capability allowing true depth-wise resolved vector field mapping. A comparative study is presented between the CLSM micro-PIV and a conventional epi-fluorescence micro-PIV. Both have been applied to the creeping Poiseuille flows in two different microtubes of 99-µm (Re = 0.00275) and 516-µm ID diameters (Re = 0.021). The CLSM micro-PIV consistently shows significantly improved particle image contrasts, the definition of "optical slicing" and measured flow vector fields more accurately agreeing with predictions based on the Poiseuille flow fields, compared to the conventional micro-PIV. The OSSM micro-PTV technique is applied for a 3-D vector field mapping in a microscopic flow and a Brownian motion tracking of nanoparticles. This technique modifies OSSM system for a micro-fluidic experiment, and the imaging system captures a diffracted particle image having numerous circular fringes instead of an in-focus particle image. The 3-D particle tracking is based on a correlation between the 3-D diffraction pattern of a particle and the defocus distance from a focal plane. A computational program is invented for the OSSM micro-PTV, and provides a 3-D velocity vector field with a spatial resolution of 5.16 µm. In addition, a concept of nonintrusive thermometry is presented based on the correlation of the Brownian motion of suspended nanoparticles with the surrounding fluid temperature. Detection of fully three-dimensional Brownian motion is possible by the use of the OSSM, and the measured value of mean square displacement (MSD) is compared fairly well with Einstein's predictions.
633

Wave effects and statistical optics in radiative transfer /

Sun, Yupin. January 2001 (has links)
Thesis (Ph. D.)--University of Chicago, Dept. of Physics, June 2001. / Includes bibliographical references. Also available on the Internet.
634

Integrated through-wafer optical monitoring of MEMS for closed-loop control

Dawson, Jeremy M. January 2002 (has links)
Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xiv, 180 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 177-180).
635

Design and development of high-performance, monolithically integrated silicon-based optical receivers /

Li, Ru, January 2000 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 169-179). Available also in a digital version from Dissertation Abstracts.
636

Stimulated Raman scattering effects in WDM fiber systems and other nonlinear phenomena /

Grandpierre, Alexandra, January 2002 (has links)
Thesis (Ph. D.)--Lehigh University, 2002. / Includes vita. Includes bibliographical references (leaves 164-175).
637

A study of photoelasticity and a photoelastic and theoretical investigation of th stress distribution in square blocks subjected to concentrated diagonal loads

Frocht, Max Mark, January 1900 (has links)
Thesis (Ph. D.)--University of Michigan, 1931. / Cover title. Reprinted froman article published in the Transactions of the American Society of Mechanical Engineers, Applied mechanics, v. 53, no. 15, Sept.-Dec., 1931, under title: Recent advances in photoelasticity. "Short bibliography": p. 15.
638

Witelonis perspectivae liber quartus Book IV of Witelo's Perspectiva : a critical edition and English translation with introduction, notes and commentary /

Kelso, Carl J., January 2003 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 594-598). Also available on the Internet.
639

Witelonis perspectivae liber quartus Book IV of Witelo's Perspectiva a critical edition and English translation with introduction, notes and commentary /

Kelso, Carl J., January 2003 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 594-598). Also available on the Internet.
640

A quantitative study of chromatic adaptation

Almack, Mary Ruth, January 1900 (has links)
Thesis (Ph. D.)--Bryn Mawr college, 1924. / Vita. Published also as Psychological review publication, Psychological monographs, vol. XXXVIII, no. 2; whole no. 174. Bibliography: p. 118.

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