Müller Group

Since photons travel with the speed of light and experience low losses, they are excellent carriers for quantum information and enable a broad range of photonic quantum technologies. Our group explores light-matter interactions at the nanoscale to realize all key ingredients which are essential for the generation, manipulation and detection of quantum states of light. Examples for such quantum states are single photons or photons entangled with other photons or spin-qubits. In future applications, the individual building blocks will either be integrated in a single chip to realize fully-integrated quantum photonic circuits or form modular building blocks for distributed quantum technologies.

Examples for these building blocks are non-classical light sources, spin-photon interfaces, quantum memories and single-photon detectors. Since every quantum system has specific advantages and disadvantages we investigate a breath of systems including semiconductor quantum dots, color centers in diamond, two-dimensional transition metal dichalcogenides and rare-earth ions embedded in complex oxide crystals. Our research spans the full range from fundamentals to applications. This includes for example the investigation of novel quantum materials, development of quantum optical techniques, design and fabrication of nanophotonic structures and quantum engineering of building blocks and devices. Examples for targeted applications include quantum communication, distributed quantum networks and quantum simulation and metrology based on photons.


Selected publications:

  • L. Hanschke, K. A. Fischer, S. Appel, D. Lukin, J. Wierzbowski, S. Sun, R. Trivedi, J. Vuckovic, J. J. Finley, K. Müller, “Quantum dot single photon sources with ultra-low multi-photon probability”, npj Quantum Information 4, 43 (2018).
  • K. A. Fischer, L. Hanschke, J. Wierzbowski, T. Simmet, C. Dory, J. J. Finley, J. Vuckovic, K. Müller, “Signatures of two-photon pulses from a quantum two-level system”, Nature Physics 13, 649–654 (2017).
  • K. Müller, K. A. Fischer, C. Dory, T. Sarmiento, K. G. Lagoudakis, A. Rundquist, Y. Kelaita, J. Vuckovic, “Self-homodyne-enabled generation of indistinguishable photons”, Optica 3, 931-936 (2016).
  • K. Müller, K. A. Fischer, A. Rundquist, C. Dory, K. G. Lagoudakis, T. Sarmiento, Y. A. Kelaita, V. Borish, J. Vuckovic, “Ultrafast Polariton-Phonon Dynamics of Strongly Coupled Quantum Dot-Nanocavity Systems”, Physical Review X 5, 031006 (2015).
  • K. Müller, A. Rundquist, K. A. Fischer, T. Sarmiento, K. G. Lagoudakis, Y. A. Kelaita, C. Sánchez Muñoz, E. del Valle, F. P. Laussy, J. Vuckovic, “Coherent Generation of Nonclassical Light on Chip via Detuned Photon Blockade”, Physical Review Letters 114, 233601 (2015).

Dr. Kai Müller


Walter Schottky Institut 
Technical University of Munich
Am Coulombwall 4
85748 Garching

Phone: +49(0) 89 / 289 - 11598
Fax:     +49(0) 89 / 289 – 12704

Email: kai.mueller@wsi.tum.de

Group webpage