Integrated single-molecule based single-photon sources for photonic quantum technologies

Maja Colautti, Pietro Lombardi, Marco Trapuzzano +7 more

The successful development of future photonic quantum technologies heavily depends on the possibility of realizing robust, reliable and, crucially, scalable nanophotonic devices. In integrated networks, quantum emitters can be deployed as single-photon sources or non-linear optical elements, provided their transition linewidth is broadened only by spontaneous emission. However, conventional fabrication approaches are hardly scalable, typically detrimental for the emitter coherence properties and bear limitations in terms of geometries and materials. Here we introduce an alternative platform, based on molecules embedded in polymeric photonic structures. Three-dimensional patterns are achieved via direct laser writing around selected molecular emitters, which preserve near-Fourier-limited fluorescence. By using an integrated polymeric design, record-high photon fluxes from a single cold molecule are reported. The proposed technology allows to conceive a novel class of quantum devices, including integrated multi-photon interferometers, arrays of indistinguishable single photon sources and hybrid electro-optical nanophotonic devices.

Maurangelo Petruzzella

Pietro Lombardi, Anna P. Ovvyan, Sofia Pazzagli +8 more

Summary form only given. Efficient quantum light sources and non-linear optical elements at the few photon level are the basic ingredients for most applications in nano and quantum technologies. On the other hand, a scalable platform for quantum information and communication typically requires reliable light matter interfaces and on-chip integration. In this work we demonstrate the potential of a novel hybrid technology which combines single organic molecules as quantum emitters and dielectric chips, consisting of ridge waveguides and grating far-field couplers [1].Here the emitters are integrated by spin-coating onto the photonic chip. We demonstrate at room temperature the emission of single photons from DBT molecules into ridge waveguides with a branching ratio up to 40%. The overall single-photon source efficiency, including emission into the guided mode, propagation losses, and emission into a quasi-gaussian mode in free space, is estimated around 16%. These results are competitive with state-of-the-art single photon emission into propagating guided modes from solid state systems [4], while offering a novel platform with unprecedented versatility. Single waveguided photons can be readily processed on-chip or efficiently extracted into a quasi-gaussian mode in free space. We also discuss options to further improve the collection efficiency and applications to quantum optics [5] and to study manybody-induced quantum correlation effects [6].

Jennifer Ann Hollingsworth

Maja Colautti, Pietro Lombardi, Marco Trapuzzano +7 more

Abstract The successful development of future photonic quantum technologies will much depend on the possibility of realizing robust and scalable nanophotonic devices. These should include quantum emitters like on‐demand single‐photon sources and non‐linear elements, provided their transition linewidth is broadened only by spontaneous emission. However, conventional strategies to on‐chip integration, based on lithographic processes in semiconductors, are typically detrimental to the coherence properties of the emitter. Moreover, such approaches are difficult to scale and bear limitations in terms of geometries. Here an alternative platform is discussed, based on molecules that preserve near‐Fourier‐limited fluorescence even when embedded in polymeric photonic structures. 3D patterns are achieved via direct laser writing around selected molecular emitters, with a fast, inexpensive, and scalable fabrication process. By using an integrated polymeric design, detected photon counts of about 2.4 Mcps from a single cold molecule are reported. The proposed technology will allow for competitive organic quantum devices, including integrated multi‐photon interferometers, arrays of indistinguishable single‐photon sources, and hybrid electro‐optical nanophotonic chips.

Costanza Toninelli, Ilja Gerhardt, Alex S. Clark +13 more