Two-photon photopolymerization directly initiated by spiropyran photochromic molecules

Here,we report the ability of spiropyrans to initiate two-photon polymerization(TPP)for the first time in the literature.The comparison and synergies between the spiropyran photochromic molecule of interest,namely 6-nitro-BIPS,and well-known photoinitiators of radical photopolymerization have been studied.The spiropyran(SPy)molecule can initiate TPP in the presence of trifunctional acrylic monomers and create true 3D structures.The comparison with Irgacure 819,a well-known Type-I photoinitiator,shows that SPy has a comparable capability for TPP.In addition,the combination of SPy with methyl diethanolamine increased the reactivity of both one-and two-photon polymerizations.In the last section,we discuss which SPy isomer is the active photochromic species capable of generating radicals for initiating two-photon polymerization.

Advanced hybrid plasmonic nano-emitters using smart photopolymer

The integration of nano-emitters into plasmonic devices with spatial control and nanometer precision has become a great challenge.In this paper,we report on the use of a smart polymer to selectively immobilize nano-emitters on specific preselected sites of gold nanocubes(GNCs).The cunning use of the polymer is twofold.First,it records both the selected site and the future emitters-GNC distance through plasmon-assisted photopolymerization.Second,because the polymer is chemically functionalized,it makes it possible to attach the nano-emitters right at the preselected polymerized sites,which subsequently recognize the nano-emitters to be attached.Since the resulting active medium is a spatial memory of specific plasmonic modes,it is anisotropic,making the hybrid nanosources sensitive to light polarization.The ability to adjust their statistical average lifetime by controlling the thickness of the nanopolymer is demonstrated on two kinds of nano-emitters coupled to GNCs:doped polystyrene nanospheres and semiconductor colloidal quantum dots.

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.