Coherent EUV Light from High-Order Harmonic Generation: Enhancement and Applications to Lensless Diffractive Imaging

<p>The first half of this thesis presents the first demonstration of quasi-phase matching in the coherent high-order harmonic conversion of ultrafast laser pulses into the EUV region of the spectrum. To achieve this quasi-phase matching, a novel method of fabricating hollow waveguides with a modulated inner diameter was developed. This technique lead to significant enhancements of EUV flux at wavelengths shorter than were previously accessible by known phase-matching techniques. In the second half of this thesis, the first tabletop demonstration of lensless diffractive imaging with EUV light is presented using HHG in a gas-filled hollow waveguide to provide coherent illumination. This tabletop microscope shows a spatial resolution of \~ 200 nm and a large depth of field. Furthermore, the technique is easily scalable to shorter wavelengths of interest to biological imaging.</p>