Thursday, July 22, 2010

Ultrafast and Ultrasmall-- Dmitri V. Voronine

The Wednesday opening session on Optical Antennas and Nanosystems was a successful highlight of the progress in extending the ultrafast technology to the nanoscale. The field of ultrafast nano-optics has many exciting potential applications but is still in the early stage of development due to the difficulties of manipulating localized subwavelength optical fields. Optical antennas are promising candidates for high harmonic generation and for the future advance of attosecond science. They can dramatically enhance field strength and the opening invited talk gave an overview of the field and new updates. I learned that waveguides can also be used to enhance HHG.

Other talks from this session covered other important aspects of ultrafast nano-optics such as coherent control, strong field photoemission, and even terahertz imaging of metamaterials. I was especially impressed by the talk of Markus Raschke about measuring the response of plasmonic nanostructures both in phase and amplitude. This information will allow a better understanding how the nanostructures work and will allow better control of their behavior. This may also show the differences between the same nanostructures fabricated using different methods and help improve the nanofabrication methods.
In the final talk of this session Tobias Hanke showed impressive results on a variety of different nanoantennas revealing their different nonlinear optical properties and pushing their dynamics investigations to the ultrafast few-cycle limit.

In the future I hope these results will be used to combine the nanoantennas with molecules and will allow performing efficient single molecule spectroscopy and control. One breakthrough talk on this topic was given by Fernando Stefani on Tuesday about coherent control of a single molecule. He showed for the first time experimental control of a single molecule as opposed to an ensemble as has been previously widely investigated for several decades. These previous studies concerned averaged information and complex optimal control pulses were often hard to interpret. Now at a single molecule level the situation will hopefully will be clearer.

Actually, a pioneer of nanoplasmonic coherent control and of adiabatic nanofocusing, and a UP committee member, Mark Stockman, was present in the audience. Several contributions used his original research for inspiration and implemented some of his ideas experimentally. It also happened to be his birthday on that day, and I and my colleagues and friends all give him our best wishes and greetings, and express our gratitude and thanks for his big enthusiasm, great ideas and scientific achievements. Happy Birthday, Mark!

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