5th Institute of Physics

Final Theses Topics

Join our team for your Bachelor/Master thesis project!

We are always looking for motivated students to join us for their Bachelor / Master thesis project.

On this page you can find a list of topics currently offered for thesis projects at the 5th Institute of Physics. Information on the research project and team in which each topic is embedded as well as contact persons are provided below.

If you are interested in joining our team for your thesis work please do not hesitate to contact us.

Phatthamon Kongkhambut and Viraatt Anasuri share their experience as students in the Master's program PHYSICS and take us to their labs at the 5th Institute of Physics.

Duration: 2:17 | © University of Stuttgart | Source: YouTube

Bachelor Thesis Topics

Highly engineered hollow core fibres (in cooperation with the Max Planck Institute in Erlangen) allow to guide light over long distances in air beyond the diffraction limit. This allows for ideal atom-light coupling. The spectroscopy of Rubidium filled fibres opens a new pathway to quantum optics.

Contact: Robert Loew, Harald Kübler

Project: Quantum Optics with Hot Atoms

Combining photonic waveguides with the spectroscopy of thermal Rubidium vapours allows for miniaturization of various spectroscopy schemes to the nanometer scale. This is not only interesting for applications but is also of fundamental interest as at such length scale the atom-wall interaction as well the atom-atom interaction become more relevant.

Contact: Robert Loew, Harald Kübler

Project: Quantum Optics with Hot Atoms

In our experiment, we plan to implement optical trapping of single ionic impurities that we create by photo-ionization of parent Rydberg impurities. For this to realize it is of importance to characterize the beam profile of a micro-meter sized optical tweezer. You will develop a fully automized Piezo-based scanning system to measure the point-spread-function of a micro-tweezer generated from a high-NA aspheric lens. The goal is to identify optimal laser beam parameters to balance diffraction limited performance and undesired geometric aberrations in view of realizing minimal spot sizes.

Contact: Florian Meinert

Project: Giant Rydberg Atoms in Ultracold Quantum Gases

The goal of this project will be to calculate the transition frequencies of our molecules by diagonalizing the molecular Hamiltonians. In a second step these calculations will be compared against actual measurements taken by the prospective student using our experimental setup. This spectroscopy has direct applications in precision measurements, where physics that usually require large-scale particle accelerators can be studied on a single optical table.

Contact: Tim Langen

Project: Cold Molecules

When laser cooling diatomic molecules dark states can arise, which do not couple to the cooling lasers anymore. Hence, the cooling stops. A way to mitigate this is to rapidly switch the polarization of the laser light. Such switching can be accomplished using a so-called Pockels cell. The topic of this thesis will be to set up such a Pockels cell, characterize and test it in the lab and apply it to remix dark states in our experiments, e.g. by slowing down a molecular beam. The latter has never been achieved with our molecules before, and would thus be a significant step forward in molecular laser cooling.

Contact: Tim Langen

Project: Cold Molecules

Master Thesis Topics

The focus of the thesis can be both theoretical or experimental. The goal of this project will be the characterization and optimization of a cold beam of dipolar molecules using laser ablation in a cryogenic cell. In the cell, collisions with a cold Helium buffer gas thermalize the molecules to 4 K. The molecular beam is formed using an exit aperture in the cell, and provides very good starting conditions for subsequent laser cooling. For a more theory focussed thesis, extensive computer simulations can be used to model and optimize the molecular beam and the dynamics inside the buffer gas cell. This will increase the available number of molecules, which will have direct applications in precision measurements. For an experimentally focussed thesis, your goal will be to plan and setup a new cryostat, implement the buffer gas cell and characterize the resulting molecular beam. 

Contact: T. Langen

Project: Cold Molecules

If you are interested in a cutting-edge interdisciplinary research on the interface of atomic physics, quantum optics, and Nano-photonics this is a proper project for you. Within the scope of this Master’s thesis, you will develop good theoretical understanding and experimental skills by working on an efficient integrated optical cavity embedded in an atomic vapor cell.

For further details please refer to this pdf file.

Contact: Tilman Pfau

Project: Quantum Optics with Hot Atoms

A Rydberg atom provide a single electron in a well defined quantum state that can cover thousands of atoms in a Bose-Einstein Condensate. We are interested to watch this single quantum imersed in a sea of atoms. On the one hand it can bind atoms into molecular states on the other habe it can backact on the collective excitations of a quantum gas. The interaction between the electron and the quantum gas is mediated by low energy scattering. The interaction depends on the electron spin and we have recently studies how this spin dependence can be used to excite very exotic "trilobite" molecules (see figure above) [2]. In this thesis we want to understand the transition from molecular physics to many-body physics [3] including the spin degree of freedom. In addition we want to study the depencence on the orbital angular momentum [4]. The experimenatl tool is high resolution spectroscopy on a BEC sample including single ion detection.

[1] Kathrin S. Kleinbach, Florian Meinert, Felix Engel, Woo Jin Kwon, Robert Löw, Tilman Pfau, Georg Raithel
"Photo-association of trilobite Rydberg molecules via resonant spin-orbit coupling"
Phys. Rev. Lett. 118, 223001 (2017)

[2] A. Gaj, A. T. Krupp, J. B. Balewski, R. Löw, S. Hofferberth, and T. Pfau
"From molecular spectra to a density shift in dense Rydberg gases"
Nature Comm. 5, 4546 (2014)

[3] A.T. Krupp, A. Gaj, J.B. Balewski, P. Ilzhöfer, S. Hofferberth, R. Löw, T. Pfau, M. Kurz, and P. Schmelcher,
"Alignment of D-state Rydberg molecules"
Phys. Rev. Lett. 112, 143008 (2014)

 

Contact: Florian Meinert

Project: Giant Rydberg Atoms in Ultracold Quantum Gases

 

In our experiment we excite nitric oxide to Rydberg states by a three-photon excitation scheme. Due to subsequent collisions the molecules are ionized. The generated charges can be measured via electrodes in the cell. This thesis will focus on the measurement of these currents and the corresponding spectroscopy cells. This comprises testing and characterisation of the fabricated cells, optimisation of the cell geometry via computer simulation and investigation of the ionisation mechanism of the Rydberg molecules. Tackling questions like the influence of space charges on the detection and checking if the generation of a pre-plasma is possible in our cell.
You will learn something about sensing technology and the detection of very small currents in the nA to pA range. Furthermore you will use modern thin film technology directly bonding microelectronics on glass surfaces involving use of the clean room facilities of the Institute for Large Area Microelectronics. Measurements in the lab will be performed with a state of the art laser system involving a UV laser, a visible and a near infrared laser.

Contact: Harald Kübler, Fabian Munkes

Project: Trace Gas Sensing

To investigate a new kind of gas sensor, we have to excite nitric oxide molecules to a Rydberg state with a three-photon excitation scheme. It was already shown that our excitation path works. However, to be as sensitive as possible with the investigated sensing principle we need to excite as many molecules to Rydberg states as possible. Therefore, this thesis will aim at the optimisation of the excitation path. This includes measurements of different molecular transitions with well controlled parameters to find the strongest transition lines as well as the investigation of predissociation of the molecules. Furthermore the signal-to-noise-ratio will be optimised by setting up frequency modulation devices and the corresponding electronics.
In the scope of this thesis you will work with a modern laser system and learn how to maintain it.  The system comprises a state of the art UV laser, a self build frequency doubled high power green laser and a near infrared tapered amplifier system. In addition you will work with an in house developed gas mixing unit and pump system to control pressure and nitric oxide flow inside the measurement setup. You will also learn to work with optical components like acousto-optic modulators, electronics like lock-in amplifiers and modern industrial technology like mass flow controllers.

Contact: Harald Kübler, Patrick Kaspar

Project: Trace Gas Sensing

The goal of this project will be to integrate 3D-printed optics with ultracold atoms. The atoms will first be cooled to microkelvin temperatures in a magneto-optical trap and then transfered into an optical tweezer. This tweezer will be formed using lenses that are directly 3D-printed onto the tip of an optical fiber by our collaborators at PI4. Their unique properties should make it possible to both trap single atoms in the tweezers and collect the fluorescence of these atoms with high efficiency. Based on this, a single photon source can be realized that will have versatile applications in quantum information processing.

Contact: Tim Langen
Project: Cold Molecules

The current state-of-the-art theoretical model to describe strongly dipolar Bose-Eintein condensates of Dysprosium is the so-called extended Gross-Pitaevskii equation. This equation is based on the mean-field Gross-Pitaevskii equation including the long-range anisotropic dipole-dipole interaction, to which an effective term is added to take into account the effect of beyond-mean-field corrections. These correction arise from quantum fluctuations in the fluid and act as an effective extra non-linearity. The goal of this project is to perform simulations of this equation to compare to experiments in order to test the thepry at the current level and make useful predictions for our experiments on Dysprosium. These numerical simultions are developped in our group, and they allow to implement the exact experimental conditions.

Contact:Tilman Pfau

Project: Dipolar Quantum Gases

In collaboration with ITO a high-numeric aperture solid-immersion lenses will be placed on a glass cell. Different lens geometries will be explored and characterized. This topic is in context of the room-temperature single-photon emitter project.

Contact: Florian Christaller, Harald Kübler

Project: Quantum Optics with Hot Atoms

This project is a collaboration with the IHFG. We plan to develop a blue laser source in a compact package based on the VECSEL-technology developed at the IHFG. This light source will be integrated in our trace gas sensor project.

The new laser source will be compared to an existing commercial laser source at the PI5.

Contact: Robert Löw, Harald Kübler

Project: Quantum Optics with Hot Atoms

The usual laser cooling in atoms relies on the spontaneous force, which arises from many individual photon absorption and emission cycles. Molecules can typically only scatter a much smaller number of photons. Moreover, they feature many internal states. Taken together, this significantly reduces the magnitude and versatility of the spontaneous force for molecules. An promising alternative are stimulated forces, where instead of spontaneously decaying back into the ground state, the molecules return to the ground state by stimulated emission. The goal of this Master's thesis will be to calculate the forces in these processes, which can be orders of magnitude higher than spontaneous forces. Once understood, we will apply them to the molecules in our experiment for the first time.

Contact: T. Langen

Project: Cold Molecules

Teacher Candidate (Lehramt) Thesis Topics

The group "Physics Didactics Research" is constantly offering various topics for your final thesis projects. To find out more on current offerings please contact:

Ronny Nawrodt

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