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Join us for the 3rd FoNS seminar:

Thursday 5th October 4-5pm in Blackett LT3, followed by a wine reception on level 8.

Speakers

    Dr Audrey de Nazelle (CEP): The many faces and facets of air pollution research

    Air pollution research is a large and complex field, requiring interactions between a huge diversity of expertise from understanding environmental processes, to monitoring, assessing and addressing impacts of air pollution and associated mitigating policies. Imperial College collectively has an impressive body of research on air quality, which the newly formed Air Quality Network aims to coalesce and build upon to amplify its impacts. My own work covers a broad span of air quality-related research, of which I will provide a brief tour, using opportunities provided by novel digital technology as a main thread to the story. Smart phone based apps and sensors provide a unique opportunity to simultaneously help researchers collect data to improve air pollution science, engage citizens in healthier and more sustainable behaviours, and encourage decision-makers in designing more health-promoting policies. At least that’s the theory, let’s see in practice, and let’s also see how the Air Quality Network can help us move the field forward.

      Professor John Tisch (Physics): Attosecond Light Sources: generating and measuring the shortest pulses available to science and the birth of Attosecond Science

        The femtosecond barrier was broken in 2001 when the first isolated, attosecond-duration (1as=10-18s) light pulses were generated by firing very intense laser pulses with carefully controlled waveforms into neon gas atoms. The duration of these pulses was 650as. The current world record stands at 53as. To put this into some kind of perspective, this is the time required for light to travel a distance equal to the size of the smallest virus.

        Attosecond light pulses provide scientists with the shortest controllable probes currently available. Such pulses, used as exquisitely sharp temporal “scalpels”, are allowing previously immeasurably fast dynamics in matter to be tracked and, potentially, even controlled at a fundamental level.

        Though a relatively new field, a growing number of groups around the world have established attosecond measurement capabilities in their laboratories, and are employing these powerful new tools to conduct ground-breaking experiments in atoms, molecules and condensed phase matter. Attosecond measurements have been made of photo-ionisation dynamics, multi-electron relaxation processes, and ultrafast nuclear rearrangements in molecules. The attosecond time-delays in photoemission from surfaces has been measured for the first time – effectively “timing the photoelectric effect” – and recently, attosecond control of the electrical and optical properties of dielectrics at optical frequencies has been demonstrated, with implications for PHz signal processing.

        Using the attosecond facilities in the Laser Consortium in the Physics Department as an exemplar, this talk will provide an accessible introduction to the science and technology behind the generation, characterisation and application of attosecond light pulses.

        Getting here