Burak Gürlek M.Sc.

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.

Molecule-photon interactions in phononic environments

Michael Reitz, Christian Sommer, Burak Gürlek, Vahid Sandoghdar, Diego-Martin Cano, Claudiu Genes

Molecular spectroscopy in the solid-state crucially depends on the interaction of electronic degrees of freedom with a highly complex vibrational environment. The large number of intramolecular vibrations (vibrons) and crystal vibrations (phonons) have often reduced the analysis of these driven molecular systems to a limited set of vibrations and numerical studies. We describe the non-equilibrium dynamics of light-matter systems comprised of guest molecules hosted in crystalline environments including finite thermal occupancies of vibrons and phonons. Using an open-system approach based on quantum Langevin equations, we provide analytical expressions for absorption and emission spectra with arbitrary numbers of vibronic and phononic modes. Exploiting the potential of this framework, we find that vibron-phonon coupling leads to a generally non-Markovian vibrational relaxation dynamics and that the common coupling to phonons can mediate collective vibron-vibron interactions similar to the processes of sub- and superradiance for radiative transitions. For molecular polaritonic scenarios with a strongly confined quantum light mode, we analytically characterize the imprint of vibronic and phononic couplings onto the cavity transmission profile and derive effective polariton cross-talk rates for finite baths occupancies.

Manipulation of Quenching in Nanoantenna–Emitter Systems Enabled by External Detuned Cavities: A Path to Enhance Strong-Coupling

Burak Gürlek, Vahid Sandoghdar, Diego-Martin Cano

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.