Dokument: Photoassociation of ultracold RbYb in an optical lattice - a quest towards absolute ground state molecules
| Titel: | Photoassociation of ultracold RbYb in an optical lattice - a quest towards absolute ground state molecules | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=63962 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20231201-110027-5 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Pollklesener, Bastian [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Görlitz, Axel [Gutachter] Prof. Dr. Philip Kollmannsberger [Gutachter] | |||||||
| Stichwörter: | Ultracold molecules, Quantum optics | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 530 Physik | |||||||
| Beschreibung: | This thesis reports on advancements of the setup of a new molecule experiment pioneered by T. Franzen [1] and photoassociation (PA) spectroscopy in ultracold mixtures of Rubidium (Rb) and Ytterbium (Yb) in optical lattices in order to find ways to produce ground state RbYb molecules.
The new apparatus is divided into three segments of stainless steel chambers, in which ultracold clouds of Rb and Yb are prepared in low-pressure environments at 1x10^-11 mbar and cooled to temperatures of μK. In the central chamber the atomic species are brought together via long distance transport over 45 cm using high-power optical dipole traps (ODTs) to enable the simultaneous preparation of Rb and Yb atom clouds. In order to produce high density mixtures of the isotopes 87Rb and 170Yb in a combined optical trap a complex experimental sequence was designed and optimised to create an ultracold mixture of 5x10^5 Rb and 9x10^4 Yb atoms with temperatures of 5.3 μK (Rb) and 1 μK (Yb) in a XODT [2]. Beyond that, the setup and loading of an even more complex final optical trap - a three dimensional optical lattice - was an essential part in this thesis and opened up the possibility for a variety of advanced experimental studies. Following the preparation of ultracold gas mixtures, this work focused on photoassociation under various trapping conditions. 1-photon-spectroscopy, where unbound atom pairs of Rb and Yb are converted to electronically excited RbYb molecules, spanning a frequency range of 0.1 - 11 GHz with a tunable and stable laser system at 556nm was conducted near the [Rb] 5s 2S1/2+[Yb] 6s 6p 3P1-asymptote of Yb in a mixture of 87Rb, |F = 1,mF = -1> and 170Yb atoms. Here the first pair of 1-photon resonances near the intercombination line of Yb with binding energies at E(B1) = -h x 3057.2(3) MHz and E(B2) = -h x3074.3(3) MHz were detected [3]. Afterwards this thesis focused on the improvements of photoassociation rates in various trap configurations aiming at tighter confinement resulting in a photoassociation rate of K(PA)-XODT = 5(2) x 10^-13 cm^3/s in a crossed optical dipole trap. In a 2D optical lattice the rate could be further increased to K(PA)-2D = 8.5(1.3) x 10^-13 cm^3/s, while a 3D lattice achieved comparable values at K(PA)-3D = 1.0(2) x 10^-12 cm^3/s. This enhancement is a significant step (compared to the value reported in [1] and [3]) as it facilitates the detection of previously unobserved weaker PA resonances. Furthermore experimental studies in optical lattices benefit from increased PA rates to enable the all-optical production of molecules in the ground state with free-bound STIRAP. With 2-photon spectroscopy the two least bound vibrational states of the ground state molecule potential could be measured with high accuracy at binding energies of E(B) (Δν'=-1) = h x 101.9(1) MHz and E(B) (Δν'=-2) = h x 1011.1(1) MHz. Using dark resonance spectroscopy the Rabi frequencies of both free-bound and bound-bound transitions could be estimated to Ω(FB) ~ 2π x 1 kHz and Ω(BB) ~ 2π x 1 MHz. Based on the results concerning photoassociation of RbYb at the intercombination line of Yb this thesis presents concepts for an improvement of the experimental setup including ways to enhance the phase space density of our dual species mixture in novel optical trap designs. These improvements we should be able to increase the PA rate in photoassociation experiments even further and create conditions for double degeneracy in the Rb-Yb mixture. Moreover, calculations of Mott Insulator transitions in this thesis propose how to prepare both atomic species in a dual Mott Insulator state in the 3D optical lattice as this promises to be the best conditions for efficient production of vibrational ground state molecules. [1] T. Franzen, “A rbyb ultracold mixture machine - from chunks of metal to intercombination line photoassociation,” Ph.D. dissertation, Heinrich-Heine-Universit¨at Düsseldorf, 2023. [2] B. Pollklesener, T. Franzen, C. Sillus, and A. Görlitz, “A new apparatus for the production of ultracold mixtures of Rb and Yb,” manuscript under preparation, 2023. [3] T. Franzen, B. Pollklesener, C. Sillus, and A. Görlitz, “Intercombination-line photoassociation spectroscopy of 87Rb170Yb,” Phys. Rev. A, vol. 107, p. 023 114, 2 2023. doi: 10.1103/PhysRevA.107.023114. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät | |||||||
| Dokument erstellt am: | 01.12.2023 | |||||||
| Dateien geändert am: | 01.12.2023 | |||||||
| Promotionsantrag am: | 16.08.2023 | |||||||
| Datum der Promotion: | 29.09.2023 |
