Print Email Facebook Twitter Optimal parameter estimation of shaped phase objects Title Optimal parameter estimation of shaped phase objects Author Villegas, Arturo (ICFO-Institut de Ciencies Fotoniques; Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/CERCA)) Passos, M. H.M. (ICFO-Institut de Ciencies Fotoniques) Pereira, S.F. (TU Delft ImPhys/Pereira group) Torres, J. (TU Delft Electrical Engineering, Mathematics and Computer Science; ICFO-Institut de Ciencies Fotoniques; Universitat Politecnica de Catalunya) Faculty Electrical Engineering, Mathematics and Computer Science Date 2024 Abstract We show a general method to estimate with optimum precision, i.e., the best precision determined by the light-matter interaction process, a set of parameters that characterize a phase object. The method is derived from ideas presented by Pezze et al. [Phys. Rev. Lett. 119, 130504 (2017)0031-900710.1103/PhysRevLett.119.130504]. Our goal is to illuminate the main characteristics of this method as well as its applications to the physics community probably not familiar with the formal quantum language usually employed in works related to quantum estimation theory. First, we derive precision bounds for the estimation of the set of parameters characterizing the phase object. We compute the Crámer-Rao lower bound for two experimentally relevant types of illumination: a multimode coherent state with mean photon number N and N copies of a multimode single-photon quantum state. We show under which conditions these two models are equivalent. Second, we show that the optimum precision can be achieved by projecting the light reflected or transmitted from the object onto a set of modes with engineered spatial shape. We describe how to construct these modes and demonstrate explicitly that the precision of the estimation using these measurements is optimum. As an example, we apply these results to the estimation of the height and sidewall angle of a cliff-like nanostructure, an object relevant in the semiconductor industry for the evaluation of nanofabrication techniques. To reference this document use: http://resolver.tudelft.nl/uuid:9d50fe88-ca05-4c00-9018-1139850b3f55 DOI https://doi.org/10.1103/PhysRevA.109.032617 ISSN 2469-9926 Source Physical Review A: covering atomic, molecular, and optical physics and quantum information, 109 (3) Part of collection Institutional Repository Document type journal article Rights © 2024 Arturo Villegas, M. H.M. Passos, S.F. Pereira, J. Torres Files PDF PhysRevA.109.032617.pdf 459.08 KB Close viewer /islandora/object/uuid:9d50fe88-ca05-4c00-9018-1139850b3f55/datastream/OBJ/view