Towards the integration of nanoemitters by direct laser writing on optical glass waveguides

A major challenge towards nanophotonics is the integration of nanoemitters on optical chips.Combining the optical properties of nanoemitters with the benefits of integration and scalability of integrated optics is still a major issue to overcome.In this work,we demonstrate the integration of nanoemitters positioned in a controlled manner onto a substrate and onto an optical ion-exchanged glass waveguide via direct laser writing based on twophoton polymerization.Our nanoemitters are colloidal CdSe/ZnS quantum dots(QDs)embedded in polymeric nanostructures.By varying the laser parameters during the patterning process,we make size-controlled QDpolymer nanostructures that were systematically characterized using optical and structural methods.Structures as small as 17 nm in height were fabricated.The well-controlled QD-polymer nanostructure systems were then successfully integrated onto a new photonic platform for nanophotonics made of an ion-exchanged waveguide.We show that our QDs maintain their light emitting quality after integration as verified by photoluminescence(PL)measurements.Ultimately,QD emission coupled to our waveguides is detected through a home-built fiber-edge coupling PL measurement setup.Our results show the potential for future integration of nanoemitters onto complex photonic chips.