Nanoparticle-assisted Stimulated-emission-depletion Nanoscopy  Event

Abstract:

Stimulated-emission depletion (STED) technique has broken the diffraction limit in fluorescence microscopy. It offers superb resolution and fast acquisition times. In a typical STED nanoscope, a focused excitation beam is spatially overlapped with a doughnut-shaped beam that de-excites emitters to the ground state everywhere except for within the center of the doughnut.

The STED nanoscope, however, has still not become a wide-spread tool, mainly because of the high intensities and complicated setup required and the nanoscope's high cost. In this talk I will show that the use of hybrid fluorescent labels consisting of a metal nanoparticle and a fluorescent emitter (or emitters) significantly improves the performance of the STED nanoscope. Specifically, we predict theoretically and show experimentally that this technique, called nanoparticle-assisted STED (NP-STED), can significantly improve the resolution, or alternatively, reduce the intensity requirements from the STED pulse and scanning speed by 1- 2 orders of magnitude; under optimal conditions it can also reduce triplet-based photo-bleaching by several mechanisms.

I will discuss various theoretical aspects of the technique, e.g., the performance dependence
on the type of metal particles, pulse durations and illumination profiles. I will also discuss the experimental implementation and our recent proof-of-principle measurements, as well as discuss the challenges overcome and those which are yet to be overcome

Biography:

Dr Yonatan Sivan received his PhD from the Tel Aviv university in physics working on nonlinear optics (solitons in complex media and propagation of intense beams in the atmosphere), and then spent a year at Purdue university with Vlad Shalaev, working on loss compensation in plasmonic nanostructures and negative refractive index metamaterials in particular using gain media. He then moved to London to work with John Pendry, where he worked on ultrafast manipulations of short optical pulses, particularly, on time-reversal of short optical pulses, and then on super-resolution microscopy assisted by plasmonics. Currently, he is a senior lecturer at Ben-Gurion University, in the south of Israel.