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Full-Text Articles in Physics
Spontaneous Emission In Microcavity Lasers, Dustin Philip Ziegler
Spontaneous Emission In Microcavity Lasers, Dustin Philip Ziegler
Theses and Dissertations
An understanding of spontaneous emission processes within microcavities is crucial in addressing the need to make tomorrow's microlasers more efficient. One approach to improving the device efficiency is to reduce the threshold input energy at which lasing begins to occur. It has been suggested that the threshold in a microcavity laser can be decreased by increasing the fraction of spontaneous emission into the lasing mode, this can be accomplished by preferentially coupling the gain medium of the laser to the electromagnetic cavity mode of interest. It therefore becomes necessary to understand the mechanism by which this coupling takes place. This …
Shock Waves In Nonequilibrium Gases And Plasmas, William M. Hilbun
Shock Waves In Nonequilibrium Gases And Plasmas, William M. Hilbun
Theses and Dissertations
An analysis and assessment of three mechanisms describing plasma/shock wave interactions was conducted under conditions typically encountered in a weakly ionized glow discharge. The mechanisms of ion-acoustic wave damping, post-shock energy addition and thermal inhomogeneities were examined by numerically solving the Euler equations with appropriate source terms adapted for each mechanism. Ion-acoustic wave damping was examined by modeling the partially ionized plasma as two fluids in one spatial dimension using the Riemann problem as a basis. Post-shock energy addition in the form of nonequilibrium vibrational energy relaxation was also examined in one spatial dimension using the Riemann problem as a …
Thermal Lattice Boltzmann Simulations Of Variable Prandtl Number Turbulent Flow, Min Soe
Thermal Lattice Boltzmann Simulations Of Variable Prandtl Number Turbulent Flow, Min Soe
Dissertations, Theses, and Masters Projects
With the advent of massively parallel processor machines, thermal lattice Boltzmann equation (TLBE) techniques offer an attractive way of handling turbulence simulations. TLBE is new form of DNS (direct numerical simulation method)--with the important advantages of being ideal for multi-parallel processors as well as being able to handle complicated geometries. Since there are many kinetic models that will reproduce the macroscopic nonlinear (compressible) transport equations, TLBE chooses that subset which can be readily solved on a discrete spatial lattice. The lattice geometry must be so chosen that the discrete phase representation of TLBE will not taint the rotational symmetric continuum …
Spectroscopic And Kinetic Studies Of Bismuth Dimers, Robert Eugene Frankin
Spectroscopic And Kinetic Studies Of Bismuth Dimers, Robert Eugene Frankin
Theses and Dissertations
The spectroscopy of high rotational levels (J ≤ 211) in Bi2 X(Og+) and A(Ou+) was investigated for 2≤v"≤5 and 0≤v'≤4 by observing total fluorescence from laser excitation. Dunham coefficients were derived that fit all observed rotational lines to within 0.01 cm-1. Franck-Condon factors were calculated and experimentally verified for transitions originating from the initially populated levels 0≤v'≤5. Vibrational energy transfer upon collision with rare gas collision partners was investigated for the low-lying vibrational levels of the A-state using spectrally resolved, continuous wave laser induced fluorescence. Vibrational transfer was adequately modeled by …