Thermally Optimized Nanoantennas for Nanometer-scale energy conversion – NATO

Focusing light on the nanoscale in order to create intense optical or thermal nanosources is probably the main challenge facing the nano-optics community, in order to power up future devices. Metallic nanoparticles and their surface plasmon resonance are ideal optical or thermal nanosources.
Optical nanosources will benefit a wide range of applications including e.g. high sensitive detection of nano-objects in chemistry and biology, enhanced Raman or hyper-Raman spectroscopy, high resolution fluorescence imaging, addressing semiconductor micro- or nanostructures, as well as many biomedical applications. Similarly, thermal nanosources will be essential to localized cancer treatment, nano-surgery, drug delivery, photothermal and photoacoustic imaging techniques, nanochemistry or optofluidics.
In this project, we aim at using the optical properties of metal nanoparticles-based nanoantennas to create controlled energy nanosources. This will contribute to adress the crucial issue of small scale energy harvesting and manipulation, which is a prerequisite to large scale energy production.
For these reasons, thermoplasmonics will probably emerge, in parallel to nanooptics, as a major subject of applied and academic studies.
The main goal of this project is the design and fabrication of thermally optimized optical nanosources, i.e. optical nanosources able to provide localize illumination while minimizing local heating or, conversely, able to create localized thermal hot spots.

The project is divided into three scientific tasks. The first task will be devoted to the characterization and qualification of different techniques to measure temperatures at small scales. A measurement standard will be developed in order to quantify the performance of each measurement technique developed in the consortium, and specifically to determine their complementarity. An important modelization work will be undertaken in order to understand and calibrate the signals from each technique and obtain quantitative temperature measurements which will be validated experimentally using the standard.
The second task aims at creating a thermally optimized nanoantenna to efficiently couple radiation from far- to near- field while minimizing local heating. This should solve important issues in the field of plasmon-based diagnosis, where the thermal destruction of analytes is the main limitation to sensitivity, when using high probe powers.
The final task will be devoted to the development of a complex architecture to maximize the conversion of optical to thermal energy, in order to create intense nanoscale heat sources. In a second step, this nanosource will be used to produce a large temperature gradient, in order to generate electrical power using the Seebeck effect. Finally, these opto-thermal conversion devices will be integrated on a thermoelectric system in order to improve its conversion rate.
The project will be carried out by combining the complementary skills of four laboratories: the Laboratoire de Nanotechnologie d’Instrumentation Optique will bring its expertise in nanofabrication, experimental nano-optics and chemical imaging, the Institut Langevin its proficiencies in nanothermics and thermal imaging by heterodyne digital holography or Brownian particle superlocalisation, the Institut Fresnel its expertise in thermal imaging through phase variation or fluorescence anisotropy measurements, and the Institut P ' its skills in near field heat modeling.