Open fiber-based cavity for spectroscopix experiments in semiconductor quantum optics

• Subject Area: Condensed Matter Physics
• Term: Funded in 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 517518181

We apply for a stabilized open fiber cavity for investigations of semiconductor structures with respect to questions of quantum optics. The cavity will be used to reach the strong ligh-matter coupling regime in a long-term stable manner for a wide range of material systems at cryogenic temperatures below 5 K, while simultaneously granting spatial resolution in the nanometer range or better. The open cavity will be applied to a wide range of quantum optical investigations for a wide range of material systems, including Rydberg excitons, Perovskites, colloidal nanoplatelets and TMDCs. In detail, we will study (a) the scaling properties of Rydberg excitons in bulk crystals and microcrystals in the strong coupling regime. (b) the quantum states of polariton condensates based on TMDCs and perovskites. Measurements of photon statistics of the emission and quantum state tomography techniques are of interest here. (c) coupling properties of semiconductor quantum technologies. For example, the question whether quantum dots may be utilized as short-term quantum buffers for quantum light emitted from semiconductor structures. The precise tunability of the light-matter interaction strength within the open cavity will be highly beneficial for matching the bandwidth of the individual components of the quantum buffer. (d) the spatially resolved properties of hypersensitive transitions in passivated Lanthanum Oxide Layers, which are highly promising for quantum sensing applications. (e) spatially resolved spectroscopy on rare-earth sulfide thin films in order to develop a thorough understanding of the magneto-optical properties of this class of materials. The tunability of the cavity resonance, the mode volume and the investigated sample position make it possible to pursue fundamentally new approaches to quantum-optical questions especially in semiconductor systems for which is has been hard so far to reach the strong coupling regime due to huge technological challenges in creating high quality Bragg resonator structures. For these materials and also for materials where strong light-matter coupling could only be reached for limiting experimental conditions, it is to be expected that long-lasting coherence properties on the scale of nanoseconds may be realized, which corresponds to huge progress in terms of quantum-optical semiconductor spectroscopy.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Offene fiberbasierte Kavität für spektroskopische Experimente in der Halbleiterquantenoptik
• Instrumentation Group: 5730 Spezielle Laser und -Stabilisierungsgeräte (Frequenz, Mode)
• Applicant Institution: Technische Universität Dortmund
• Leader: Professor Dr. Marc Alexander Aßmann