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PRODID:Icfo
X-PUBLISHED-TTL:P1W
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UID:69d25644ecae1
DTSTART:20230412T133000Z
SEQUENCE:0
TRANSP:OPAQUE
LOCATION:Auditorium 
SUMMARY:ICFO | ROBIN CAMPHAUSEN
CLASS:PUBLIC
DESCRIPTION:Entangled photon pairs can enhance optical imaging capabilities
 . Phase imaging allows detecting fine detail of transparent samples withou
 t potentially invasive fluorescent labelling\, and here entanglement enabl
 es a higher signal-to-noise ratio (SNR) than possible with only classical 
 light. Spatial correlations from spontaneous parametric down conversion (S
 PDC) photon pair sources can also be used to increase spatial resolution a
 nd robustness to noise and aberrations in imperfect optical systems. Quant
 um imaging therefore represents a powerful approach to push imaging scienc
 e beyond its current limits.\nUntil recently\, the principal barrier to im
 plementing useful quantum imaging schemes based on entangled photons has b
 een technological\, as scalable image sensors capable of multi-photon imag
 ing were unavailable. However\, this situation has changed with the develo
 pment of single photon avalanche diode (SPAD) array cameras\, as well as e
 fficient high brightness entangled photon pair sources based on SPDC. Thes
 e advances have led to the required components now approaching relative te
 chnological maturity\, opening the window towards engineering useful and s
 calable systems that exploit entanglement in order to improve optical imag
 ing.\nIn this thesis\, we show the development of a quantum imaging platfo
 rm able to perform practical and fast spatially resolved multi-photon coin
 cidence imaging with high SNR. Special focus is placed on wide-field entan
 glement-enhanced phase imaging capability\, in order to extend experimenta
 l sensitivity beyond limits imposed by classical light. The main component
 s of our platform are: sources of hyper-entangled photon pairs\, a large f
 ield-of-view optical imaging system with phase measurement capabilities\, 
 and coincidence imaging using SPAD array cameras. More specifically\, the 
 thesis describes:\n\nThe first realization of a wide-field entanglement-en
 hanced phase imager. Wide-field here refers to the ability to acquire imag
 es across the entire field-of-view simultaneously (i.e. without need for p
 ixel-to-pixel scanning\, sometimes also called full-field). Quantum-enable
 d super-sensitivity in phase imaging beyond the capability of equivalent c
 lassical measurement is demonstrated by careful experimental noise and res
 ource analysis methods. Our system&rsquo\;s capabilities were tested throu
 gh several sample measurements corresponding to use cases with real-world 
 relevance\, including nanometre-scale feature step heights in transparent 
 material\, biomedical protein microarrays\, as well as birefringent phase 
 samples.\nThe development of general experimental and numerical tools to c
 alculate photon pair coincidence images and videos from SPAD array cameras
 \, with photon-counting and time-tagging readout modalities\, as well as t
 he retrieval of phase images resulting from multi-photon entanglement inte
 rference\, by adapting techniques from interferometry and holography. We p
 erformed also a detailed study and optimization of the influence of differ
 ent experimental parameters resulting image quality factors.\nThe evolutio
 n and optimization of our system towards real-time quantum imaging capabil
 ity. Acquisition speed is a key element of usefulness\, and in this thesis
  we integrate\, first\, a visible-wavelength entangled photon source\, and
  second\, a novel time-tagging SPAD array camera. The resulting entangleme
 nt-enabled imager presents an improvement by at least four orders of magni
 tude in measurement speed compared to previous state-of-the-art demonstrat
 ions\, resulting in the ability to record &sim\;Hz frame rate entangled ph
 oton pair coincidence videos. We show that this system\, besides phase ima
 ging\, has additional applications in the form of real-time entangled stat
 e fidelity monitoring\, and real-time point spread function characterizati
 on of optical systems\, which has important applicability to adaptive opti
 cal imaging.\n\n&nbsp\;\nWednesday April 12\, 15:30 h. ICFO Auditorium\nTh
 esis Director: Prof Dr. Valerio Pruneri
DTSTAMP:20260405T123204Z
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