| Zugriffsnummer | 21844 |
| Dokumenttyp | Dissertation |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | Towards the quantum noise limit in Ramsey-Bordé atom interferometry |
| Autor(in); Institution |
Nazarova, Tatiana; 4.3, Quantenoptik und Längeneinheit, PTB-Braunschweig
|
| Quelle/Jahr | (2007), 90 S. |
| Dissertationsvermerk | Dissertation, Universität Hannover, 2007 |
| Freie Schlagworte | Ramsey-Bordé atom interferometer ; Frequency stability of an atom interferometer ; high stable lasers ; quantum projection noise ; Dick effect |
| Zusammenfassung | In this work, the relevant noise sources in atom interferometers of Ramsey-Bordé type were investigated, which are the noise of the excitation induced by the interrogation and the noise of the detection of the excitation. In the first part of the work, the methods for the considerable reduction of the frequency noise of the interrogation laser in the low and in the high frequency range are described and demonstrated in the experiment. The coupling of vibrations onto the reference cavity was analysed and a novel mounting configuration for the reference cavity allowing to reduce the frequency noise in the low frequency range was realized. This mounting reduces the sensitivity to vibrations by two orders of magnitude in the vertical and one order of magnitude in the horizontal direction compared to the previous suport from below. Furthermore, the reduction of the high-frequency laser frequency noise using the filtering through an optical cavity is demonstrated and the influence of the high-frequency noise on the frequency stability of an atom interferometer was studied. In the second part of this work, the scheme for the detection of the quantum state of the atoms was improved. The scheme allows now the quantum projection noise limited detection of 4 · 106 atoms. Atom-intererometric measurements were performed on ensembles of 4 · 106 ultracold calcium atoms at 20 μK using the improved interrogation laser system and the improved detection scheme and the short-term stability of the atom interferometer was characterized. From the observed signal-to-noise ratio a frequency stability of the atom interferometer of σy (1 s) = 7 · 10-15 was determined for the cycle time of 50 ms. The achieved stability, which is now limited by the Dick effect, is one order of magnitude above the quantum projection noise limit. |
