Dr. Tobias Utikal

  • Wissenschaftlicher Referent (Research Coordinator)
  • Room: A.3.232
  • Telephone: +49 9131 7133316
  • E-mail

My research interest ranges from cryogenic Nano-Quantum-Optics with single emitters to Nano-Bio-Photonics using iSCAT microscopy. As research coordinator of the division I am involved in many research projects pushing the experiments forward, coordinating resources, and preserving the knowledge in the group. In various exploratory side-projects I am breaking new ground for future experiments.

I am always interested in the latest technology developments of narrow-band lasers, cryogenics, nano-positioning, microscopy at and beyond the diffraction limit, single photon detectors, and scientific cameras.

2023

Spectral splitting of a stimulated Raman transition in a single molecule

Johannes Zirkelbach, Burak Gürlek, Masoud Mirzaei, Alexey Shkarin, Tobias Utikal, Stephan Götzinger, Vahid Sandoghdar

Physical Review Research 5 043244 (2023) | Journal | PDF

The small cross-section of Raman scattering poses a great challenge for its direct study at the single-molecule level. By exploiting the high Franck-Condon factor of a common-mode resonance, choosing a large vibrational frequency difference in electronic ground and excited states and operating at T<2K, we succeed at driving a coherent stimulated Raman transition in individual molecules. We observe and model a spectral splitting that serves as a characteristic signature of the phenomenon at hand. Our study sets the ground for exploiting the intrinsic optomechanical degrees of freedom of molecules for applications in solid-state quantum optics and information processing.

On-chip interference of scattering from two individual molecules

Dominik Rattenbacher, Alexey Shkarin, Jan Renger, Tobias Utikal, Stephan Götzinger, Vahid Sandoghdar

Optica 10 1595-1601 (2023) | Journal | PDF

Integrated photonic circuits offer a promising route for studying coherent cooperative effects of a controlled collection of quantum emitters. However, spectral inhomogeneities, decoherence, and material incompatibilities in the solid state make this a nontrivial task. Here, we demonstrate efficient coupling of a pair of Fourier-limited organic molecules embedded in a polyethylene film to a TiO2 microdisc resonator on a glass chip. Moreover, we tune the resonance frequencies of the emitters with respect to that of the microresonator by employing nanofabricated electrodes. For two molecules separated by a distance of about 8 µm and an optical phase difference of about pi/2, we report on a large collective extinction of the incident light in the forward direction and the destructive interference of its scattering in the backward direction. Our work sets the ground for coherent coupling of several quantum emitters via a common mode and realization of polymer-based hybrid quantum photonic circuits.

Quantum Efficiency of Single Dibenzoterrylene Molecules in p-Dichlorobenzene at Cryogenic Temperatures

Mohammad Musavinezhad, Alexey Shkarin, Dominik Rattenbacher, Jan Renger, Tobias Utikal, Stephan Götzinger, Vahid Sandoghdar

The Journal of Physical Chemistry B 5353-5359 (2023) | Journal | PDF

We measure the quantum efficiency (QE) of individual dibenzoterrylene (DBT) molecules embedded in p-dichlorobenzene at cryogenic temperatures. To achieve this, we combine two distinct methods based on the maximal photon emission and on the power required to saturate the zero-phonon line to compensate for uncertainties in some key system parameters. We find that the outcomes of the two approaches are in good agreement for reasonable values of the parameters involved, reporting a large fraction of molecules with QE values above 50%, with some exceeding 70%. Furthermore, we observe no correlation between the observed lower bound on the QE and the lifetime of the molecule, suggesting that most of the molecules have a QE exceeding the established lower bound. This confirms the suitability of DBT for quantum optics experiments. In light of previous reports of low QE values at ambient conditions, our results hint at the possibility of a strong temperature dependence of the QE.

Tobias Utikal studied Physics at University of Bonn from 2001 to 2007. For his Diploma thesis on “Ultrafast Spectroscopy of Metallic Photonic Crystals” he moved to University of Stuttgart where he worked in the group of Prof. Harald Giessen. The following PhD thesis on “Ultrafast Nonlinear Spectroscopy of Hybrid Plasmonic Systems” he partially conducted at the Max Planck Institute for Solid State Research in Stuttgart. In 2011 he joined the Group of Prof. Vahid Sandoghdar at ETH Zurich as a postdoc. After the move of the group to the Max Planck Institute for the Science of Light (MPL) in Erlangen he became a permanent senior scientist and is acting as research coordinator of the division. In his function as safety officer he is member of the work safety council of the institute. Tobias has been elected as the scientific staff representative of MPL from 2015 – 2021.

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