Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 15 of 15 for “"sub-doppler"”.
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New techniques for sub-Doppler spectroscopy of molecular ions
… new methods for performing high-resolution sub-Doppler spectroscopy of molecular ions in the laboratory. Molecular ions are of interest to a variety of fields, from astrochemistry to fundamental physics to the study of chemical reactive intermediates. The limiting factor in developing a …
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Chemical physics and astrochemistry of H3+ and sub Doppler mid infrared spectroscopy of molecular ions
… spectroscopy. Then, an instrument for performing sub-Doppler spectroscopy of molecular ions in a liquid nitrogen cooled plasma is discussed. This instrument offers ultra high sensitivity, and sufficient accuracy and precision that rotational frequencies suitable for observational astronomy can be …
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Acetylene-filled pressure broadened short photonic microcells
… the P13 PMC line center shift with respect to sub-Doppler center is small according to experimental data. Data show that the PMC line center shift from the sub-Doppler feature for PMC no. 53 with 83% contamination was -15.4 ± 3.3 MHz which is a fractional value of 7.7×10⁻⁸ with respect to the …
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High resolution spectroscopy of the Vanadium oxide B⁴ [pi] -X⁴ [sigma] ⁻ (0,0) Band
… B⁴Π—X⁴Σ⁻ (0,0) band of VO has been recorded at sub-Doppler resolution by intermodulated fluorescence spectroscopy. Spectral linewidths of 60 MHz were typical; which enabled the hyperfine structure due to the ⁵¹V nucleus (I = 7/2) to be resolved for most of the observed branches. The hyperfine …
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Design, construction, and characterization of an ultra-sensitive, high-precision fast ion-beam spectrometer for the study of molecular ions
… lines. Fast ion beam spectroscopy allows for sub-Doppler absorption spectra to be recorded. While some techniques, such as velocity modulation spectroscopy, provide semi-rigorous ion/neutral discrimination, the spectrometer employed in this dissertation provides a rigorous, spatial …
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Application of Carbon Dioxide Waveguide Lasers to Infrared Saturation Spectroscopy
… The general principles are resolution limits of sub- Doppler saturation spectroscopy are also covered. The second part is a compendium of measurements taken and insights gained using the completed spectrometer. Collisional transitions between the hype fine components of a methyl iodide absorption …
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Using saturated absorption spectroscopy on acetylene-filled hollow-core fibers for absolute frequency measurements
… necessary to realize features narrower than the Doppler broadened overtone transitions, and most setups to date have occurred in free-space. Hollow-core photonic crystal fibers offer a potential alternative to free-space setups through their small cores (~10’s of µm) and low-loss guidance. …
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Laser cooling of rubidium atoms in a magneto-optical trap
… with emphasis on experimental parameters. Three sub-Doppler cooling mechanisms, 'sisyphus cooling', 'motion-induced orientation cooling' and the 'magnetically-assisted sisyphus effect', are described and their role in optical molasses and the magneto-optical trap is discussed. A new study of the …
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A single-site resolution fermionic quantum-gas microscope
… induced transparency (EIT) cooling instead of sub-Doppler molasses cooling.;EIT cooling occurs when a coherent driving of a three-level system generates a spectrally narrow Fano-like resonance which can be set to favour red-sideband transitions over blue ones of the quantised vibrational levels …
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Bose-Fermi mixtures of ultracold gases of dysprosium
… temperature (Chapter 7). Such novel anisotropic sub-Doppler laser cooling of Dy, which breaks the symmetry in cooling, is due to Dy's large magnetic spin aligned along a strong axis of the quadrupole field of the MOT, and we further support this plausible conjecture with the velocity selective …
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High resolution spectroscopy of some gaseous transition metal containing diatomic molecules
… of niobium nitride (NbN) have been recorded at sub-Doppler resolution by intermodulated laser-induced fluorescence. The C³Π and e¹Π states, which belong to the same electron configuration (4dδ)¹(4dπ)¹, interact strongly with each other by a second-order spin-orbit/Fermi contact mechanism; the …
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Sensitive and high-precision rovibrational spectroscopy of molecular ions relevant to astronomical and quantum chemistry
… and fundamentally important molecular ions. The sub-Doppler technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy (NICE-OHVMS) combines the sensitivity of cavity-enhanced methods with the selectivity of velocity modulation. In this work, a NICE-OHVMS …
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Development Of A Cold Atoms Platform For A DQC1 Implementation
… in a Magneto-Optical Trap (MOT) and cooled to sub-Doppler temperatures. The atoms are then subsequently trapped in the dipole trap. Our dipole trapping setup is based on a high numerical aperture lens (NA=0.53) to achieve a sub-micron trapping potential and simultaneously observe trapped atoms …
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A tunable Bose-Einstein condensate for quantum interferometry
The subject of this thesis is the use of BECs for atom interferometry. The standard way atom interferometry is today performed is by interrogating free falling samples of atoms. The employed samples are cold (but not condensed) to have high coherence, and dilute, not to interact significantly with …
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A new apparatus to simulate fundamental interactions with ultracold atoms
… for sufficiently long times, with a mixture subject to Zeeman differential energy shifts, requires a specific effort to remove magnetic field fluctuations: a rough estimate suggests that in order to maintain the system coherence for a sufficiently long time to study its dynamics, magnetic …