My current research activities encompass the theoretical investigation of topics in quantum optics, plasmonics, phononics, optomechanics and metamaterials, with particular focus on light-matter interactions from atomic to nanometer scale.
High-resolution vibronic spectroscopy of a single molecule embedded in a
Johannes Zirkelbach, Masoud Mirzaei, Irena Deperasińska, Boleslaw Kozankiewicz, Burak Gürlek, Alexey Shkarin, Tobias Utikal, Stephan Götzinger, Vahid Sandoghdar
The Journal of Chemical Physics
Vibrational levels of the electronic ground states in dye molecules have not been previously explored at high resolution
in solid matrices. We present new spectroscopic measurements on single polycyclic aromatic molecules of dibenzoter-
rylene embedded in an organic crystal made of para-dichlorobenzene. To do this, we use narrow-band continuous-wave
lasers and combine spectroscopy methods based on fluorescence excitation and stimulated emission depletion (STED)
to select individual vibronic transitions at a resolution of ∼30 MHz dictated by the linewidth of the electronic ex-
cited state. In this fashion, we identify several exceptionally narrow vibronic levels in the electronic ground state with
linewidths down to values around 2 GHz. Additionally, we sample the distribution of vibronic wavenumbers, relax-
ation rates, and Franck-Condon factors, both in the electronic ground and excited states for a handful of individual
molecules. We discuss various noteworthy experimental findings and compare them with the outcome of DFT cal-
culations. The highly detailed vibronic spectra obtained in our work pave the way for studying the nanoscopic local
environment of single molecules. The approach also provides an improved understanding of the vibrational relaxation
mechanisms in the electronic ground state, which may help to create long-lived vibrational states for applications in
Engineering long-lived vibrational states for an organic molecule
The optomechanical character of molecules was discovered by Raman about one century ago. Today, molecules are promising contenders for high-performance quantum optomechanical platforms because their small size and large energy-level separations make them intrinsically robust against thermal agitations. Moreover, the precision and throughput of chemical synthesis can ensure a viable route to quantum technological applications. The challenge, however, is that the coupling of molecular vibrations to environmental phonons limits their coherence to picosecond time scales. Here, we improve the optomechanical quality of a molecule by several orders of magnitude through phononic engineering of its surrounding. By dressing a molecule with long-lived high-frequency phonon modes of its nanoscopic environment, we achieve storage and retrieval of photons at millisecond time scales and allow for the emergence of single-photon strong coupling in optomechanics. Our strategy can be extended to the realization of molecular optomechanical networks.
Quantum metamaterials with magnetic response at optical frequencies
Rasoul Alaee Khanghah, Burak Gürlek, Mohammad Albooyeh, Diego-Martin Cano, Vahid Sandoghdar
We propose novel quantum antennas and metamaterials with strong magnetic response at optical frequencies. Our design is based on the arrangement of natural atoms with only electric dipole transition moments at distances smaller than a wavelength of light but much larger than their physical size. In particular, we show that an atomic dimer can serve as a magnetic antenna at its antisymmetric mode to enhance the decay rate of a magnetic transition in its vicinity by several orders of magnitude. Furthermore, we study metasurfaces composed of atomic bilayers with and without cavities and show that they can fully reflect the electric and magnetic fields of light, thus, forming nearly perfect electric/magnetic mirrors. The proposed quantum metamaterials can be fabricated with available state-of-the-art technologies and promise several applications both in classical optics and quantum engineering.
suggested by editors
Molecule-photon interactions in phononic environments
Michael Reitz, Christian Sommer, Burak Gürlek, Vahid Sandoghdar, Diego-Martin Cano, Claudiu Genes
Physical Review Research
Molecules constitute compact hybrid quantum optical systems that can interface photons, electronic degrees of freedom, localized mechanical vibrations, and phonons. In particular, the strong vibronic interaction between electrons and nuclear motion in a molecule resembles the optomechanical radiation pressure Hamiltonian. While molecular vibrations are often in the ground state even at elevated temperatures, one still needs to get a handle on decoherence channels associated with phonons before an efficient quantum optical network based on optovibrational interactions in solid-state molecular systems could be realized. As a step towards a better understanding of decoherence in phononic environments, we take here an open quantum system approach to the nonequilibrium dynamics of guest molecules embedded in a crystal, identifying regimes of Markovian versus non-Markovian vibrational relaxation. A stochastic treatment, based on quantum Langevin equations, predicts collective vibron-vibron dynamics that resembles processes of sub- and super-radiance for radiative transitions. This in turn leads to the possibility of decoupling intramolecular vibrations from the phononic bath, allowing for enhanced coherence times of collective vibrations. For molecular polaritonics in strongly confined geometries, we also show that the imprint of optovibrational couplings onto the emerging output field results in effective polariton cross-talk rates for finite bath occupancies.
Manipulation of Quenching in Nanoantenna–Emitter Systems Enabled by External Detuned Cavities: A Path to Enhance Strong-Coupling
We show that a broadband Fabry Perot microcavity can assist an emitter coupled to an off-resonant plasmonic nanoantenna to inhibit the nonradiative channels that affect the quenching of fluorescence. We identify the interference mechanism that creates the necessary enhanced couplings and bandwidth narrowing of the hybrid resonance and show that it can assist entering into the strong coupling regime. Our results provide new possibilities for improving the efficiency of solid-state emitters and accessing diverse realms of photophysics with hybrid structures that can be fabricated using existing technologies.
Ph.D. in Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany; Thesis on “Theoretical Analysis and Modeling of Quantum Nanophotonic Systems”
M.Sc.A in Electrical Engineering, Ecolé Polytechniqué de Montréal, Montréal, QC, Canada; Thesis on “Analysis and Design of Magnet-less Non-Reciprocal Metamaterial Structures”
B.Sc. in Mathematics Engineering, Istanbul Technical University, Istanbul, Turkey; “Summa Cum Laude”; Thesis on “Analysis of Higher Order On-Surface Radiation Condition Method for Scattering Problems”
B.Sc. in Telecommunication Engineering, Istanbul Technical University, Istanbul, Turkey; “Summa Cum Laude”; “Artificial Neural Network Method for Buried Object Detection Problems”
Graduate Research Assistant, Max Planck Institute for the Science of Light, Erlangen, Germany
Graduate Research Assistant, Ecolé Polytechniqué de Montréal, Montréal, QC, Canada
Undergraduate Research Assistant, Istanbul Technical University, Electromagnetics Research Group, Istanbul, Turkey
Honors and Awards
Selected to participate in 69th Lindau Nobel Laureate Meeting, Council for the Lindau Nobel Laureate Meetings
The First Ranked Student among 70 students from the Telecommunication Engineering Department, Istanbul Technical University
The First Ranked Student among 100 students from the Mathematics Engineering Department, Istanbul Technical University
The First Ranked Student among 250 students from the Faculty of Electrical and Electronics Engineering, Istanbul Technical University
The First Ranked Student among 200 students from the Faculty of Science and Letters, Istanbul Technical University
Double Major Program Award, Graduated from Two undergraduate programs within 4 years, regular time to graduate from one program, Istanbul Technical University
The Ord. Prof. Bedri Karafakioglu Award the by Faculty of Electrical and Electronics Engineering (EEE), Istanbul Technical University, 2011. This award is given to the most successful graduate of the year by the Faculty of EEE
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