Nano-optomechafluidics – NOFX2015

The present project intends to develop a novel hybrid “nano-optomechafluidics” measurement platform, whose original principle is based on coupling a strongly focused laser beam to the vibrations of a low-dissipation suspended nano-channel. This concept holds a considerable potential, with very high mutual benefits in both fields of nano-optomechanics and nanofluidics.

On the one hand, the nanofluid can be used for tuning key parameters involved in the nano-optomechanical interaction (e.g. refractive index, optical absorption…). This is essential in the context of exploring the limits of sensitivity and associated backaction mechanisms for the nano-optomechanical interaction, which remains poorly understood. Moreover, the nanochannel can also be fed using optically active particles (molecules, nano-diamonds, colloidal quantum dots…), which can be subsequently trapped using the tweezers geometry of the apparatus, thereby forming a so-called “quantum hybrid nano-optomechanical system”. Beside a much higher loading efficiency compared to currently existing methods, such configuration will enable a significant decrease of the required trapping power, thanks to the benefit of the intrinsic restoring force of the nanochannel. This will represent a significant asset towards reaching the quantum regime of hybrid nanomechanical systems.

On the other hand, the exquisite sensitivity enabled by the nano-optomechanical detection can serve for measuring real-time properties of the nanofluid. Firstly, the envisioned nano-optomechanical coupling scheme has been recently shown to enable broadband, high-frequency detection of the internal thermodynamic state of nanomechanical resonators. These unique abilities can serve for ultra-sensitive tracking of the evolution of the thermodynamic parameters of the nanofluid (e.g. temperature, density, viscosity…), with unprecedented time resolution. This appears as a very appealing perspective for general and versatile, ultra-sensitive sensing purposes, notably for bio-related applications. Secondly, it has been recently shown that nanomechanical resonators can be operated in such a way that they become spatially sensitive to the changes of their environments. Transposed to the nanochannel envisioned in the present context, these advanced measurement strategies will enable real-time tracking of single particles traveling inside the nano-capillary, that is a local measurement of nanofluid transport properties at the nanometre scale which has so far remained unavailable.

The project will associate the complementary expertise of three young researchers specialized in nano-optomechanics (Project Coordinator, MCF), nanofluidics (Project Participant, CR2), and in nano-fabrication (Project Participant, IR).