| Zugriffsnummer | 33325 |
| Dokumenttyp | Dissertation |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | Precision measurement of the isotopic shift in calcium ions using photon recoil spectroscopy |
| Autor(in); Institution |
Gebert, Florian; QUEST Institute for Experimental Quantum Metrology, PTB-Braunschweig
|
| Quelle/Jahr | (2015), XIV, 107 S. |
| Dissertationsvermerk | Dissertation, Universität Hannover, 2015 |
| URL | |
| Freie Schlagworte | isotopic shift ; uv single mode photonic crystal fiber ; stimulated Raman adiabatic passage (STIRAP) ; photon recoil spectroscopy |
| Zusammenfassung | Within the scope of this thesis, precision isotope shift measurements using a new spectroscopy technique were performed. The method is based on quantum logic spectroscopy, where the quantized motional states are utilized to transfer the spectroscopic information onto a second ion, the logic ion. This ion is used for sympathetically cooling and the detection of the spectroscopic signal. Photon recoil spectroscopy extends quantum logic spectroscopy to enable frequency measurements of transitions with relatively short lifetime. For further optimizing the developed method new technologies were investigated, which enable an improved control of the ions in the trap and consequently improve the signal to noise ratio of the spectroscopic technique. On the one hand, new photonic crystal fibers were investigated for single mode guidance of ultraviolet (UV) Radiation and implemented in the setup. These fibers enable an improved coherent manipulation of the logic ion through a reduction of intensity fluctuations at the position of the ion. Another improvement was achieved using the technique of stimulated Raman adiabatic passage (STIRAP), where time-dependent laser pulses are used for coherent manipulation of the state of the ion. The technique enables efficient detection of the motional groundstate population and consequently improves the expected spectroscopic signal. After the characterization of the new spectroscopic technique, isotope shift measurements were performed on different calcium isotopes. For this purpose the different ions were isotope-selectively loaded into the trap and successively investigated spectroscopically. The isotope shift is among others caused by the change in the nuclear Charge radius due to the different number of neutrons in the core. Therefore, measurements of the isotopic shift enable investigations of the structure of the nucleus. For this investigation Ca+ is an interesting candidate since here two isotopes with so-called magical Neutron numbers are stable and naturally abundant. Additionally, the results of the isotope measurements are needed to improve the comparison of laboratory data with astrophysical measurements to reveal possible time and space variations of fundamental constants. |
