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  Partner: UNT Libraries
 Degree Discipline: Physics
 Degree Level: Master's
 Collection: UNT Theses and Dissertations
Theoretical Study of Second Harmonic Generation of a Blue Laser at 486 nm Using a BBO Crystal in a Standing Wave Buildup Cavity

Theoretical Study of Second Harmonic Generation of a Blue Laser at 486 nm Using a BBO Crystal in a Standing Wave Buildup Cavity

Date: May 2002
Creator: Khademian, Ali
Description: For a spectroscopy purpose, we are interested in producing continuous wave (CW) UV laser light at 243 nm with at least 2 mW power. The theory of nonlinear optics suggests that we should be able to produce a desired 2.9 mW of 243 nm light by second harmonic generation (SHG) from a 50 mW blue laser at 486 nm using a BBO crystal in a build up cavity. The most important physical parameters are calculated. A 10 mm Brewster cut BBO crystal can provide phase matching conditions for coupling two ordinary photons at 486 nm and make a secondary beam at 243 nm. The single pass conversion efficiency is calculated not to be enough to generate 2.9 mW of SH light. My investigation shows that a standing wave build up cavity can provide a buildup factor of 94 and an overall conversion efficiency of 5.9% if one use an input coupler mirror with 1.1% transmission at 486 nm.
Contributing Partner: UNT Libraries
Photoelectric Emission Measurements for CVD Grown Polycrystalline Diamond Films

Photoelectric Emission Measurements for CVD Grown Polycrystalline Diamond Films

Date: August 1999
Creator: Hassan, Tarek
Description: We examined CVD grown polycrystalline diamond films having different methane concentrations to detect defects and study the possible correlation between the methane concentration used during the growth process and the defect density. SEM and Raman results show that the amorphous and sp2 carbon content of the films increases with methane concentration. Furthermore, photoelectric emission from diamond is confirmed to be a two-photon process, hence the electrons are emitted from normally unoccupied states. We found that the photoelectric yield, for our samples, decreases with the increase in methane concentration. This trend can be accounted for in two different ways: either the types of defects observed in this experiment decrease in density as the methane concentration increases; or, the defect density stays the same or increases, but the increase in methane concentration leads to an increase in the electron affinity, which reduces the overall photoelectric yield.
Contributing Partner: UNT Libraries
Transport Phenomena in Indium Arsenide at Low Temperatures

Transport Phenomena in Indium Arsenide at Low Temperatures

Date: August 1968
Creator: Luke, Paul Jacob
Description: This thesis looks at the transport phenomena in indium arsenide at low temperatures.
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Solutions of the Equations of Radiative Transfer by an Invariant Imbedding Approach

Solutions of the Equations of Radiative Transfer by an Invariant Imbedding Approach

Date: January 1969
Creator: Adams, Charles N.
Description: This thesis is a study of the solutions of the equations of radiative transfer by an invariant imbedding approach.
Contributing Partner: UNT Libraries
Monte Carlo Calculations of Reflected Intensities for Real Spherical Atmospheres

Monte Carlo Calculations of Reflected Intensities for Real Spherical Atmospheres

Date: January 1969
Creator: Montgomery, John A.
Description: To calculate the emergent radiation field, a realistic atmospheric model and algorithm must be developed. The radiation field may be characterized by the emergent intensities of scattered light. This is possible only if the algorithm determines these intensities as dependent upon atmospheric and angular parameters.
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Boundary Scattering of Electrons in Thin Cadmium Single Crystals

Boundary Scattering of Electrons in Thin Cadmium Single Crystals

Date: August 1968
Creator: Fortmayer, Gary William
Description: In the present investigation, zinc was plated onto a cadmium crystal to determine the effect on the scattering parameter.
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Size Effect in the Electrical Conductivity of Bismuth

Size Effect in the Electrical Conductivity of Bismuth

Date: August 1967
Creator: Vaughn, Bobby J.
Description: If a physical dimension of a metallic specimen is comparable with, or smaller than, the mean free path of the conduction electrons, then the observed electrical conductivity will be less than that of a conventional bulk sample. This phenomenon is called a size effect, and is the result of electron scattering from the specimen surfaces. In the present investigation, measurements were made on electropolished monocrystalline specimens ranging from matchbox geometry to thick-film geometry in order to obtain further information on the size effect in bismuth at liquid helium temperatures.
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The Effects of Lead Placement and Sample Shape in the Measurement of Electrical Resistivity

The Effects of Lead Placement and Sample Shape in the Measurement of Electrical Resistivity

Date: August 1970
Creator: Stephens, Anthony E.
Description: This thesis is a study of the effects of lead placement and sample shape in the measurement of electrical resistivity.
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A Determination of the Bothe Depression Factor for Discs in Water

A Determination of the Bothe Depression Factor for Discs in Water

Date: August 1950
Creator: Patton, Bob
Description: The purpose of this work is to determine experimentally the depression of the neutron density by a detecting foil. The depression factor is known as the "self-shading" of the foil.
Contributing Partner: UNT Libraries
A Study of the Decay Levels of 169/Tm69

A Study of the Decay Levels of 169/Tm69

Date: December 1970
Creator: Harris, Robert J.
Description: The purpose of this investigation was to study the radiations of the 169/Tm nucleus as it de-excites after the electron capture decay of the 169/Yb. Numerous unreported gammas were present in the sample. The origins of these gamma rays were found.
Contributing Partner: UNT Libraries
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