BEGIN:VCALENDAR
VERSION:2.0
PRODID:Icfo
X-PUBLISHED-TTL:P1W
BEGIN:VEVENT
UID:69d0cb3aef8ad
DTSTART:20230426T090000Z
SEQUENCE:0
TRANSP:OPAQUE
LOCATION:ICFO Homage room and Online (Teams)
SUMMARY:ICFO | ARTURO VILLEGAS JUÁREZ
CLASS:PUBLIC
DESCRIPTION:Resolution enhancement in modern optical metrology techniques h
 as been possible due to significant technological improvements. The accura
 te and precise control of wavelength\, bandwidth\, and power of light sour
 ces\; homogeneity\, high-quality composition materials and surface smoothn
 ess of optical elements\; and highly stable nanopositioners and optomechan
 ical components\, allow more sensitive imaging and sensing\, in certain sc
 enarios even beyond the standard diffraction limit. This has motivated a m
 ore detailed study of the fundamental resolution limitations of an optical
  system.\nThe chosen approach to address this problem is to consider optic
 al imaging as a parameter estimation problem. With this in mind\, the theo
 ry of quantum estimation and statistical inference provides the tools to d
 etermine the estimation precision limits. Starting by considering the stat
 e of light as a quantum state that carries information of interest\; the C
 r&aacute\;mer-Rao lower bound provides a fundamental limit for the achieva
 ble precision. This lower bound is directly associated to optical resoluti
 on in practical terms.\nIn this thesis\, we present an overview of the use
 ful tools of quantum estimation theory that can be applied to optical metr
 ology. We focus on the Cr&aacute\;mer-Rao lower bound\, and provide method
 s to calculate it. Since the bound depends on specific characteristics of 
 the system\, we explore three specific possibilities.\nFirst we present wi
 th an example the validity regimes for different bounds\; explicitly&nbsp\
 ;to calculate the parameters of entangled photon pairs in&nbsp\;the frame 
 of&nbsp\;a quantum Lidar System.\nSecond\, we show the dependency of the l
 ower bound on the photonic model selection\, showing a discrepancy between
 &nbsp\;N copies of a single photon and a multimode coherent state with ave
 rage photon number N.\ntwo particular models. Third\, we study the effects
  of lossy environments in the informational content of the quantum state.\
 nAdditionally\, we present the conditions that a measuring strategy must s
 atisfy to allow attainability of the fundamental limit.\nIf the measuremen
 t strategy is not feasible or it is not possible to implement\, one can ev
 aluate the resolution improvement of the available technique by comparing 
 to the standard and fundamental limits.\nFor specific scenarios of interes
 t\, measurement methods based on the use of spatial modes of light allow t
 o asymptotically attain the resolution limit. This has drawn attention to 
 the information carried by specific modes\, and has motivated the design o
 f measurement strategies based on probing or sensing using spatial modes. 
 In this thesis we include an overview of spatial modes of light\, their ge
 neration and detection\, and their use for optical sensing. We present a m
 ethod for optical beam localization in the transverse plane using spatial 
 mode information. Moreover\, we propose a technique to retrieve the full m
 odal decomposition of an arbitrary beam\; which combined with the adequate
  set of modes allows to estimate certain parameters of an optical state wi
 th the maximum precision possible.\n&nbsp\;\nThesis Director: Prof Dr. Jua
 n P&eacute\;rez Torres
DTSTAMP:20260404T082634Z
END:VEVENT
END:VCALENDAR