BEGIN:VCALENDAR VERSION:2.0 PRODID:Icfo X-PUBLISHED-TTL:P1W BEGIN:VEVENT UID:69d4b3e1b5470 DTSTART:20251202T090000Z SEQUENCE:0 TRANSP:OPAQUE LOCATION:ICFO Auditorium SUMMARY:ICFO | ALEXANDER DEMUTH CLASS:PUBLIC DESCRIPTION:Two-photon quantum correlations are a resource for quantum comm unication\, sensing\, and imaging. Coincidence-based quantum imaging lever ages spatiotemporal quantum correlations to form images from two-photon co incidences rather than intensity alone. To be useful beyond free-space lab oratory setups\, such as in access-constrained\, realistic settings\, quan tum correlations must be distributed through compact waveguides while rema ining usable after propagation across many spatial modes and at practical rates.\nThis thesis develops methods for waveguide-based quantum imaging b y integrating and advancing three main technology components: engineered q uantum light sources based on spontaneous parametric down-conversion (SPDC )\, optical waveguides (including disordered and multicore optical fibre)\ , and detection with single-photon avalanche diode (SPAD) array cameras\, through both time-tagging and rolling-delay compensation. We demonstrate a nd quantify transport of quantum spatiotemporal correlations\, and impleme nt quantum imaging in a waveguided geometry using optical fibre. In additi on\, we show real-time operation with continuous coincidence image frames. The main specific achievements are:\n- Foundations for correlation transp ort.\n \; \; \; We model the propagation of quantum correlated SPDC two-photon states in media (continuous and discrete pictures)\, iden tifying measurable signatures of correlation conservation after transport. \n \; \; \; We develop a protocol that measures the waveguide point-spread function via coincidence imaging with a time-tagging SPAD arr ay and timestamp post-processing.\n \; \; \; Using these tools \, we define metrics to certify and quantify correlation transport through waveguides\, and map its dependence on waveguide parameters.\n- Waveguide -based transport of SPDC correlations\n \; \; \; We validate t ransmission of SPDC spatiotemporal correlations through a custom-fabricate d transverse Anderson localization optical fibre and a commercially availa ble multicore fibre (MCF)\, showing high-dimensional\, mode-parallel deliv ery of correlations necessary for coincidence imaging protocols. We inject position anticorrelated photon pairs into the fibres\, extract coincidenc es from SPAD array timestamps\, characterize the waveguide point-spread fu nction through the coincidence-imaging protocol and quantify preservation of correlations.\n- Waveguided quantum ghost imaging.\n \; \;  \; Building on the established quantum correlation distribution\, we imple ment waveguided quantum ghost imaging (QGI) through a MCF using a non-dege nerate signal-idler photon pair SPDC source. The idler illuminates the sam ple through the waveguide and is detected with a single SPAD\, while the s ignal\, which has not interacted with the sample\, is imaged with spatial resolution on a SPAD array camera. We report image quality and imaging rat es\, and identify limits of optical resolution.\n- Real-time quantum ghost imaging.\n \; \; \; We realize real-time\, low-latency QGI (f ree-space and waveguided) by leveraging in-pixel asynchronous coincidence extraction in the SPAD array camera\, eliminating external post-processing latency. Coincidence image frames are produced continuously\, supporting live alignment and use.\nTogether\, these results provide methods for wave guided\, mode-parallel delivery and measurement of quantum correlations us ing optical fibre transport and SPAD array camera coincidence imaging\, an d thus extend quantum imaging technology towards practical waveguided sett ings. This may outline routes to applications in constrained environments\ , low photon flux regimes\, and imaging at unusual wavelengths\, potential ly enabling new use-cases for quantum imaging\, for example in the life sc iences.\n \;\nTuesday December 02\, 10:00 h. ICFO Auditorium \nThesis Director: Prof. Dr. Valerio Pruneri DTSTAMP:20260407T073601Z END:VEVENT END:VCALENDAR