Optically Driven Plasmonic Nanomotors
February 21st, 2018 MIKAEL KÄLL Chalmers University of Technology

Optical trapping using focused laser beams has been proven extremely useful for contact-less manipulation of a variety of small objects, including colloidal plasmonic nanoparticles [1]. We found that single-crystal gold nanorods could be easily trapped by laser tweezers and driven to rotate at frequencies above 40 kHz (2.5x106 r.p.m.) by applying circularly polarized laser light with power as low as a few mW [2]. The particles thus function as tiny rotational nanomotors driven by light [3]. The driving torque, caused by transfer of photon angular momentum (spin), is dominated by plasmonic resonant scattering rather than absorption, which drastically reduces laser-heating effects and allows for sensitive control of the optomechanical properties through the particles nanoscale morphology. I will discuss various aspects on this phenomenon and its applications, which include sensitive thermometry and biomolecular analysis and actuation. If there is time, I will also briefly discuss recent work on surface supported plasmonic antennas for biosensing.

Seminar, February 21, 2018, 12:00. ICFO’s Seminar Room

Hosted by Prof. Romain Quidant