Theory of Nonlinear Propagation of High Harmonics Generated in a Gaseous Medium

Introduction to High-Order Harmonic Generation.- Background.- Single-Atom Response.- Macroscopic Propagation Effects.- Applications of High-Order Harmonic Generation.- Thesis Outline.- Theoretical Tools.- Introduction.- Time-Dependent Schrödinger Equation.- Maxwell's Wave Equation.- Far-Field Harmonic Emission.- Medium Propagation Effects in High-Order Harmonic Generation of Ar.- Introduction.- Macroscopic HHG Spectra: QRS vs TDSE.- Macroscopic HHG Spectra: Theory vs Experiment.- Disappearance of Cooper Minimum in the HHG Spectra of Ar.- Macroscopic Wave Packet.- Wavelength Scaling of Harmonic Efficiency.- Conclusion.- Comparison of High-Order Harmonic Generation of Ar Using a Truncated Bessel or a Gaussian Beam.- Introduction.- Simulation of HHG Spectrum of Ar.- Phase Matching Conditions at the Low Gas Pressure.- Pressure Induced Phase Mismatch.- Conclusion.- Generation of an Isolated Attosecond Pulse in the Far Field by Spatial Filtering with an Intense Few-Cycle Mid-Infrared Laser.- Introduction.- Macroscopic HHG Spectra of Xe Using an 1825-nm Few-Cycle Laser.- Spatiotemporal Evolution of Fundamental Laser Field.- Time-Frequency Representation of High Harmonics.- Spectral and Spatial Filtering in Generation of Attosecond Pulses.- CEP Dependence of Isolated Attosecond Pulses.- Comparison Between QRS and SFA in Modeling Propagation Effects.- Conclusion.- Effects of Macroscopic Propagation and Multiple Molecular Orbitals on the High-Order Harmonic Generation of Aligned N2 and CO2 Molecules.- Introduction.- HOMO contribution in HHG of Random and Aligned N2 Molecules.- Intensity Dependence of Multiple Orbital Contributions in HHG of Aligned N2 Molecules.- Shape Resonance in Photoionization and Harmonic Generation of N2 Molecules.- Contributions of Multiple Molecular Orbital in HHG of Aligned CO2 Molecules.- Major Factors that Influence Positions of the Minima in the HHG Spectra of Aligned CO2 Molecules.- Conclusion.- Photoelectron Angular Distributions in Single-Photon Ionization of Aligned N2 and CO2 Molecules Using XUV Light.- Introduction.- Connection Between Photoionization and harmonic Generation.- Total Photoionization Yield from Aligned N2 and CO2 Molecules.- Photoelectron Angular Distributions (PADs) of Fixed-in-Space N2 Molecules in the Laboratory Frame.- PADs of Transiently Aligned N2 Molecules in the Laboratory Frame.- Photon Energy Dependence of PADs for Aligned N2 Molecules.- PADs of Transiently Aligned CO2 Molecules in the Laboratory Frame.- Conclusion.-Summary.