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International audience; The recent development of silicon photonics, namely based on Si and Si derivative materials (e.g. Si3N4), has enabled the integration of a wide range of optical devices onto the same chip. However, due the intrinsic limitations of silicon, some devices cannot be efficiently integrated in silicon monolithic architectures. III-V/ Si wafer bonding and LiNBO3 thin film technologies have already provided a path to increase the functionalities that can be heterogeneously integrated onto silicon chips, now turned hybrid [1]. Two-dimensional materials represent another promising route to complement the properties of silicon and create compact hybrid architectures with novel functionalities. The most mature of these 2D materials, graphene, has attracted lots of attention as it exhibits attractive nonlinear optical properties, such as a large photo-refractive Kerr index, and saturable absorption, which might be interesting for nonlinear photonic chips and all-optical information processing. While its intrinsic properties are relatively high for a monolayer-thick material, the use of integrated optics provides a way to enhance the otherwise low absolute response of this 2D material. Besides, the capability of tuning graphene optical properties provides an additional advantage to realize on-demand and reconfigurable nonlinear photonic devices. I will here discuss some of these developments, including our recent demonstration of hybrid graphene/ Si3N4 waveguides for chip-based saturable absorbers [2]. Our work also shows that hybrid graphene coated waveguides provide a relevant platform to unravel the dynamics of graphene nonlinear optical properties. Finally, some limitations of graphene nonlinear properties lead us to explore, with our Australian collaborators, alternative 2D materials such as graphene oxide [3], which might represents an interesting trade-off in terms of linear absorption and nonlinearity.

A novel approach to integrating biochip and microfluidic devices is reported in which microcontact printing is a key fabrication technique. The process is performed using an automated microcontact printer that has been developed as an application-specific tool. As proof-of-concept the instrument is used to consecutively and selectively graft patterns of antibodies at the bottom of a glass channel for use in microfluidic immunoassays. Importantly, feature collapse due to over compression of the PDMS stamp is avoided by fine control of the stamp’s compression during contact. The precise alignment of biomolecules at the intersection of microfluidic channel and integrated optical waveguides has been achieved, with antigen detection performed via fluorescence excitation. Thus, it has been demonstrated that this technology permits sequential microcontact printing of isolated features consisting of functional biomolecules at any position along a microfluidic channel and also that it is possible to precisely align these features with existing components.