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UID:69e22d04aecb7
DTSTART:20260227T090000Z
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TRANSP:OPAQUE
LOCATION:ICFO Auditorium
SUMMARY:ICFO | JOSEPH ALAN WINDLEY WRAGG
CLASS:PUBLIC
DESCRIPTION:Stimulating an object and watching what the object does in resp
 onse is the basis of scientific discovery. As much is true for much of exp
 erimental nanophotonics\, where a material is stimulated with light and we
  observe how the material responds with nanometric precision. In this thes
 is I describe the development of a new approach to experimental nanophoton
 ics: Action Microspectroscopy.\nThe exploration of how light and matter in
 teract holds the key to understanding\, then harnessing\, the properties o
 f matter. For instance\, light harvesting materials require a deep underst
 anding of their interaction with energy in order to engineer an optimal co
 mbination of light absorption and the ensuing conversion to charge.\nThe s
 yntheses of new optoelectronic materials with exotic properties need preci
 sion techniques to observe such properties in action and the unexpected co
 nsequences such properties may have. As the leading edge of technology del
 ves deeper into the nanoscale\, approaches to explore matter on the same s
 cale must be devised to keep pace.\nAction Microspectroscopy is a Fourier 
 transform excitation spectroscopy platform designed to energetically\, spa
 tially and temporally diagnose the excited state in atomic systems. Its de
 velopment came in stages\, each benchmarked by a chapter in this thesis. F
 irstly\, I demonstrated that the spectral response of many single molecule
 s in a widefield image could be simultaneously acquired\, meaning that spa
 tial and spectral detail could be combined to diffractionlimited precision
 .\nThe second step was to focus on the outcome of the excited state in a t
 wo dimensional semiconductor\, WSe2. By studying the material&rsquo\;s res
 ponse in fluorescence and photocurrent\, it was possible to determine whic
 h exciton (excited state electrons bound to positive holes) states were mo
 re likely to lead to charge conversion and which were more likely to re-re
 leasetheir energy as a photon.\nFinally\, by combining spatial detail with
  temporal resolution in photocurrent detection\, I show that the measureme
 nt of the exciton-specific transfer of energy in materials can be achieved
 . I obtain spatially resolved pump-probe measurements of exciton states in
  WSe2\, with a view to spatially resolved 2 dimensional electron spectrosc
 opy.\nFriday February 27\, 10:00 h. ICFO Auditorium Thesis Director: Prof 
 Dr. Niek Van Hulst and Dr. Luca Bolzonello
DTSTAMP:20260417T125220Z
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