BEGIN:VCALENDAR VERSION:2.0 PRODID:Icfo X-PUBLISHED-TTL:P1W BEGIN:VEVENT UID:69d289e70ee3e DTSTART:20230412T100000Z SEQUENCE:0 TRANSP:OPAQUE LOCATION:ICFO Auditorium SUMMARY:ICFO | VALERIO DI GIULIO CLASS:PUBLIC DESCRIPTION: \;\nAmong the fundamental constituents of matter\, charged particles such electrons and positrons are leading protagonists in physic al phenomena associated with small (~ meV) and high (~ MeV) energy scales. For example\, conductive electrons in condensed-matter systems can collec tively respond to the action of an external electromagnetic field and sust ain plasmon excitations that dominate their visible optical behavior. The presence of material boundaries produces a dramatic modulation of such mod es\, allowing us to mold their interaction with light for the exploration of fundamental phenomena and the design of practical applications\, which are central themes in the field of nanophotonics.\nElectrons traveling in free space\, such as those in electron microscopes\, constitute ideal prob es for imaging materials with nanometric resolution. In an effort to push energy resolution down to the meV regime and simultaneously perform time-r esolved measurements with fs precision\, laser and electron pulses in tran smission electron microscopes can now be synchronized to meet at the speci men in the so-called photon-induced near-field electron microscopy (PINEM) . Here\, efficient electron coupling to intense laser-driven evanescent fi elds results in a strong energy reshaping of the electron wave function. O ver the last decade\, PINEM has been used to tailor the wave function of f ree electrons\, thus emphasizing the role of these microscopy probes as in formation carriers.\nThis Thesis lies in this general and broad context as an effort to explore new scenarios in the interaction between free electr ons and optical excitations. In particular\, Chapter 2 addresses the theor etical investigation of quantum-mechanical aspects associated with PINEM i nteraction by means of a quantum-optics description of the optical field. Building up on those results\, in Chapter 3 we show that improved control over electron pulse shaping\, compression\, and statistics can be gained b y replacing coherent laser excitation by interaction with quantum light\, such as phase- and amplitude-squeezed optical fields.\nChapter 4 explores the role played by fluctuations of the electromagnetic vacuum in the coupl ed dynamics of a free-electron beam and a macroscopic object\, producing e lastic diffraction and decoherence. In particular\, we show that diffracti on can dominate over decoherence\, therefore suggesting a nondestructive a pproach to microscopy based on the specific choice of parameters that mini mize the inelastic interaction with the specimen.\nAs a radically differen t aspect of electron-light interaction\, Chapter 5 is devoted to the study of the interference produced in the cathodoluminescence emission by the s ynchronized interaction of free electrons and dimmed laser pulses scattere d by the specimen. Here\, we argue that such effect may enable measurement s combining the spectral and temporal selectivity of the light with the at omic resolution of electron beams to resolve the phase associated with opt ical modes in the sample.\nIn Chapter 6\, we consider that elastic diffrac tion\, similar to that studied in Chapter 4\, is also experienced by condu ction electrons in a two-dimensional material\, therefore altering the pro perties of the latter by simply adding a neighboring neutral structure.\nG oing to higher energy scales\, Chapter 7 explores the potential of confine d optical modes to assist electron-positron pair production arising from t he scattering of gamma rays by surface polaritons propagating along a mate rial interface.\nIn summary\, throughout this Thesis we exploit the coupli ng between evanescent light\, harnessed in the vicinity of material bounda ries\, and charged free particles in order to access new effects only foun d at the point where nanophotonics\, quantum optics and high-energy physic s meet through strong light-matter interaction.\n \;\nWednesday April 12\, 12:00 h. ICFO Auditorium and Online (Teams)\nThesis Director: Prof Dr . Javier Garcí\;a de Abajo DTSTAMP:20260405T161223Z END:VEVENT END:VCALENDAR