Dokument: Development and Characterization of an Ion Trap Apparatus for Spectroscopy of Single Molecular and Atomic Ions
| Titel: | Development and Characterization of an Ion Trap Apparatus for Spectroscopy of Single Molecular and Atomic Ions | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=61866 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20230131-141847-5 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Wellers, Christian [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Schiller, Stephan [Gutachter] Prof. Dr. Görlitz, Axel [Gutachter] | |||||||
| Stichwörter: | Single-ion trapping; molecular spectroscopy; sympathetic cooling; molecular hydrogen ion | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 530 Physik | |||||||
| Beschreibung: | A novel system for the spectroscopic analysis of single atomic or molecular ions has been developed, set up and put into operation. Its main purpose is to study the molecular hydrogen isotopologues H2+, D2+ and HD+, which are theoretically the simplest manageable molecular ions. By measuring different rovibrational transitions and combining the results, important fundamental constants can be determined. In particular, these are the three mass ratios (electron-proton, electron-deuteron and deuteron-proton) and the Rydberg constant.
In order to compete with other measurement methods, high-precision measurements of rovibrational transition frequencies on HD+, H2+ and D2+ with a relative frequency uncertainty u = 1E-12 are required. This is better than the current theoretical relative uncertainty u = 7E-12. The molecular hydrogen ion cannot be observed directly, which is why a single fluorescent beryllium ion is employed. An ion pair consisting of a single atomic ion and the molecular ion can be laser cooled and is an essential diagnostic tool for mass spectroscopy of the molecular ion or for its state detection. For example, continuous mass spectrometry can be used to observe chemical reactions of the molecular ion with the residual gas in the vacuum chamber. The currently used method of state-dependent photodissociation is also inconvenient in the case of a single molecular ion and should be replaced by non-destructive detection. A variant based on quantum logic requires a laser system that can cool the oscillation mode of the two-ion system to the ground state. This laser has been built. A second method uses a state-dependent optical dipole force (ODF). The effect of the ODF is calculated for relevant states in HD+ and possible spectroscopy scenarios are discussed. In particular, a spectroscopy scheme is presented that will allow comparison to the latest results from the ensemble study. It includes the state preparation using radiofrequencies and is based on a non-destructive state detection technique. Further alternatives of spectroscopy are proposed, as well as extensions and improvements to the system, some of which have already been initialised. It turns out that the two-ion quantum system behaves differently from previous works investigating ensemble systems. Those consist of a few ten hydrogen molecules surrounded by a few hundred beryllium ions. In this work, it can no longer be assumed that the ion is in any desired initial state and the state must be specifically prepared. With the ensemble system, it can be statistically assumed that at least some ions are in the desired state. This work presents an important milestone on the way to high-precision spectroscopy of a single molecular hydrogen ion. A complex apparatus, consisting of an ultra-high vacuum system with integrated particle trap, detectors and beryllium ovens has been developed from scratch. The laser systems needed for laser cooling and spectroscopy of a single molecular ion have been built and integrated into the system. With the presented system, single HD+ ions have been trapped, identified and successfully performed spectroscopy for the first time. The apparatus has been analysed for systematic effects using the beryllium ions. A radiofrequency (rf) spectroscopy of the hyperfine transition in the beryllium ground state allows the determination of the magnetic field strength at the ion's location. This is necessary for high precision spectroscopy and provides important insides into the upcoming rf spectroscopy of molecular hydrogen. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Physik » Experimentalphysik | |||||||
| Dokument erstellt am: | 31.01.2023 | |||||||
| Dateien geändert am: | 31.01.2023 | |||||||
| Promotionsantrag am: | 23.08.0022 | |||||||
| Datum der Promotion: | 25.11.0023 |
