Integrated plasmonic dimers: A platform for ultra-efficient trapping of nanoparticles

In this contribution, the efficient trapping of low refractive index nanoparticles, with radii down to 50 nm, is numerically demonstrated in gold dimers coupled with SOI waveguides. This coupled scheme provides a strong excitation of the plasmonic resonators [1] that, in combination with the field enhancement occurring in dimers, leads to an ultra-efficient trapping. Without any needs of cumbersome optical elements, this excitation scheme does not affect the overall portability of the system and stands out as a perfect candidate for integration inside microfluidic systems [2], for nanoparticle immobilisation and analysis. The possibility to trap smaller nanoparticle, with radii down to 5 nm, having higher refractive index will be discussed. The impact of the geometrical parameters of the dimer on the optomechanical well stiffness and depth, the optimisation strategies, the simple fabrication approach and the ongoing experimental demonstration will be as well detailed. [1] M. Fevrier, P. Gogol, A. Aassime, R. Megy, C. Delacour, A. Chelnokov, A. Apuzzo, S. Blaize, J.-M. Lourtioz et B. Dagens, ≪Giant Coupling Effect between Metal Nanoparticle Chain and Optical Waveguide,≫ Nano Letters, pp. 1032-1037, 2012. [2] G. Magno, A. Ecarnot, C. Pin, V. Yam, P. Gogol, R. Megy, B. Cluzel et B. Dagens, ≪Integrated plasmonic nanotweezers for nanoparticle manipulation,≫ Optics Letters, vol. 41, n° 16, 2016.