LMI Seminar: Hot Nanophotonics: Let’s do something useful with metal losses
Romain Quidant, ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), & ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona
Recent years have witnessed a growing interest in controlling temperature on the nanoscale motivated by applications to different fields, including information technology, chemistry and medicine. Under illumination at its plasmon resonance, a metal nanoparticle features enhanced light absorption, turning it into a nano-source of heat, remotely controllable by light. By combining efficient light-to-heat conversion, strong temperature gradients and fast time dynamics, plasmon-enabled heating (also known as Thermoplasmonics) opens a wide range of new opportunities over standard heating schemes. So far, extensive efforts have already been put into exploiting those assets in the context of nanomedicine and high-density data storage.
In this talk, we propose to extend the range of applications that can benefit from Thermoplasmonics with a focus on three main technologies:
Plasmon-powered optofluidics and biosensing – In this first part of the talk, we aim at controlling fluids dynamics on the micro-scale as a way to improve the performance of integrated plasmon-based biosensing platforms. By creating a temperature gradient between two planar electrodes, we induce a controllable electrothermooptical effect capable to direct the fluid towards the sensing region of the chip, resulting in a faster binding dynamics and larger resonant shift . We also demonstrate the possibility to engineer the temperature gradient to achieve more complex optofluidic functionalities .
Electrically driven varifocal metalens – By cascading a static Si-based metalens with a thermo-optical module, we achieve a varifocal lens. We demonstrate how a proper micro-engineering of the thermal landscape enables to vary the focal distance by up to 25% at 12V. We fully characterize the beam quality, showing little aberration introduced by the heating module, and measure the response time in the 1-100ms range. The technology is successfully validated in the context of microscopy . Remarkably, it is shown that our approach enables us to go beyond a simple lens and achieve a wide range of more complex phase landscapes .
Plasmon-assisted 3D printing – In this last example, we study the use of nanoplasmonics to overcome some major limitations of light-powered 3D-printing. In particular, we demonstrate that a solution of gold nanorods, engineered to resonate in the near infrared region of the spectrum, can be used as an invisible plasmonic ink for light-induced sintering of polymer powders. When compared with current strategies using carbon black inks, our approach offers an increase sintering efficiency and enables a full control over the printing color .
[1[ J. Garcia-Guirado, R. Rica, J. Ortega, J. Medina, V. Sanz, E. Ruiz-Reina, R. Quidant, Overcoming diffusion-limited biosensing by electrothermoplasmonics, ACS Photonics 5, 3673 (2018)
 B. Ciraulo et al, In preparation
 A. Afridi, J. Canet-Ferrer, L. Philippet, J. Osmond, P. Berto, R. Quidant, Electrically-driven varifocal metalens, ACS Photonics, 5, 4497-4503 (2018)
 P. Berto, L. Philippet, A. Afridi, J. Osmond, G. Tessier, R. Quidant, Tunable free-form planar optics, submitted (2018)
 A. W. Powell, A. Stavrinadis, I. de Miguel, G. Konstantatos, R. Quidant, White and brightly colored 3D printing based on resonant photothermal sensitizers, Nano Lett. 18, 6660-6664 (2018)