Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)
Efficient on-chip interface for many-body quantum optics with single molecules
Pierre Türschmann, Nir Rotenberg, Jan Renger, Tobias Utikal, Stephan Götzinger, Vahid Sandoghdar
Abstract
Summary form only given. A current challenge and trend in optical sciences is to extend the toolbox generated from experiments with single emitters and single photons towards interfacing photons with a well-defined number of quantum emitters. The resulting complex optical network would enable studies of many-body quantum optical phenomena and could lend itself to quantum simulations. However, common light-matter interfaces via strong focusing or cavity enhancement do not scale favourably. Therefore, achieving many-body coupling while preserving control of the individual quantum systems poses remarkable experimental challenges.Here, we present an inherently scalable platform, which relies on the evanescent coupling of single dye molecules to subwavelength TiO2waveguides (nanoguides) that are embedded in an organic matrix (Fig. 1a). At liquid helium temperatures, we observe lifetime-limited linewidths for these molecules distributed over an inhomogeneously broadened spectrum. However, by using integrated microelectrodes, we can Stark shift the resonances over a large bandwidth. The dopant concentration determines the optical density of our system which can reach up to a few hundred molecules per cubic wavelength. The highly confined mode of a nanoguide allows a substantial mode overlap with the emission pattern of a single emitter, resulting in coupling efficiencies of up to 32%. Therefore, we can observe coherent extinction signals from many different molecules in the transmission signal of a nanoguide; an example is shown by the blue curve in Fig. 1b [1]. The green and red curves in Fig. 1b demonstrate the nonlinear behaviour of a molecule when driven with a second narrow-band laser [1, 2]. We show that by modifying the spectral properties of the molecules either via external optical or static electric fields we control the optical response of a nanoguide. In addition to discussing subtleties of design and fabrication, we elaborate on future efforts towards the realization of on-chip polaritonic states [3] and the integration of further optical elements such as micoresonators [4].