The peculiar properties of quantum optical states represent a new resource for innovative imaging schemes, as sub shot noise imaging or quantum illumination. In particular, quantum entanglement and squeezing have significantly improved phase estimation and imaging in interferometric settings beyond the classical limits. In this proceeding, after a general introduction, I will describe part of the recent work on quantum imaging performed in INRIM concerning phase imaging and light field ghost imaging.
The peculiar properties of quantum optical states represent a new resource for innovative imaging schemes, as sub shot noise imaging or quantum illumination. In particular, quantum entanglement and squeezing have significantly improved phase estimation and imaging in interferometric settings beyond the classical limits. In this proceeding, after a general introduction, I will describe part of the recent work on quantum imaging performed in INRIM concerning phase imaging and light field ghost imaging.
The peculiar properties of quantum optical states represent a new resource for innovative imaging schemes, as sub shot noise imaging or quantum illumination. Here we present in detail two works realized in INRIM. The first involves exploiting entanglement to enhance the imaging of a pure phase object in a non-interferometric setting. This wide-field method, based on the "transport of intensity equation", provides the absolute value of the phase without prior knowledge of the object. It does not require spatial and temporal coherence of the incident light. Besides improving image quality at a fixed number of photons, we demonstrate a clear reduction of the uncertainty in the quantitative phase estimation. This research also paves the way for applications at different wavelengths, e.g., x-ray imaging, where reducing the photon dose is of utmost importance. Then, we demonstrate a novel imaging technique, named Light Field Ghost Imaging, which exploits light correlations and light field imaging principles to enable overcome the limitations of ghost imaging in a wide range of applications. Notably, our technique removes the requirement to have prior knowledge of the object distance allowing us to refocus in post-processing and to perform 3D imaging while retaining all the benefits of GI protocols.
ABSTRACT We review our last results in the field of quantum imaging obtained at INRIM Keywords: Quantum Imaging, Entanglement, Quantum Correlations, Sub shot noise measurements 1. INTRODUCTION Quantum properties of the optical field represent a resource of the utmost relevance for the development of quantum technologies, allowing unprecedented results in disciplines ranging from quantum information and metrology to quantum imaging. In particular, in the last case various protocols have been proposed ranging from ghost imaging [1,2], to quantum illumination [3] and sub-shot-noise quantum imaging [4]. Sub-shot-noise measurements with quantum optical states (for example exploiting the quantum correlations of Parametric Down Conversion (PDC) emission) provide the possibility of the detection of weak objects, a task that could have important practical applications. A little more in detail the principle of this technique is to take advantage of the correlation in the noise of two conjugated branches of PDC emission: in fact, s ubtracting the noise measured on one branch from the image of a weak object obtained in the other branch, the image of the object, previously hidden in the noise, could be restored. A schematic implemen tation of this protocol is depicted in Figure 1. On the other hand, ghost imaging technique allows to retrieve information about the object using spatial resolution detector from light (one arm of correlated beams) that does not interact directly with the object, whereas the photons transmitted thr ough (or reflected by) the object are registered by a bucket detector, which does not resolve the shape of the object.
Abstract In previous years the possibility of creating and manipulating quantum states of light has paved the way for the development of new technologies exploiting peculiar properties of quantum states, such as quantum information, quantum metrology and sensing, quantum imaging, etc. In particular quantum imaging addresses the possibility of overcoming limits of classical optics by using quantum resources such as entanglement or sub-Poissonian statistics. Albeit, quantum imaging is a more recent field than other quantum technologies, e.g. quantum information, it is now mature enough for application. Several different protocols have been proposed, some of them only theoretically, others with an experimental implementation and a few of them pointing to a clear application. Here we present a few of the most mature protocols ranging from ghost imaging to sub shot noise imaging and sub-Rayleigh imaging.
Quantum imaging can be defined as an area of quantum optics that investigates the ultimate performance limits of optical imaging allowed by the quantum nature of light. Quantum Imaging techniques possess a high potential for improving the performance in recording, storage, and readout of optical images beyond the limits set by the standard quantum level of fluctuations known as the shot noise. This talk aims at giving an overview of the fundamentals of Quantum Imaging as well as its most important directions. We shall discuss generation of the spatially multimode squeezed states of light be means of a travelling-wave optical parametric amplifier. We shall demonstrate that this kind of light allows us to reduce the spatial fluctuations of the photocurrent in a properly chosen homodyne detection scheme with a highly efficient CCD camera. It will be shown that using the amplified quadrature of the light wave in a travelling-wave optical parametric amplifier, one can perform noiseless amplification of optical images. We shall provide recent experimental results demonstrating a single-shot noiseless image amplification by a pulsed optical parametric amplifier. One of important experimental achievements of Quantum Imaging, coined in the literature as quantum laser pointer, is a precise measurement of position and transverse displacement of a laser beam with resolution beyond the limit imposed by the shot noise. We shall describe briefly the idea of the experiment in which the transverse displacement of a laser beam was measured with resolution of the order of Angstrom. The problem of precise measurement of transverse displacement of a light beam brings us to a more general question about the quantum limits of optical resolution. The classical resolution criterion, derived in the nineteen century by Abbe and Rayleigh, states that the resolution of an optical instrument is limited by diffraction and is related to the wavelength of the light used in the imaging scheme. However, it was for a long time recognised in the literature that in some cases when one has some a priori information about the object, one can improve the resolution beyond the Rayleigh limit using the so-called super-resolution techniques. As a final topic in this talk, we shall discuss the quantum limits of optical super-resolution. In particular, we shall formulate the standard quantum limit of super-resolution and demonstrate how one can go beyond this limit using specially designed multimode squeezed light.
G.Ortolano,A.Paniate,P.Boucher,C.Napoli,S.Soman,S.Pereira,I.Ruo Berchera,M.Genovese The peculiar properties of quantum optical states represent a new resource for innovative imaging schemes [1], as sub-shot noise imaging [2] or quantum illumination [3]. Here, after a general introduction, we present a work where photon number entanglement is exploited to enhance imaging of a pure phase object in a non-interferometric setting. Our method provides the absolute value of the phase without prior knowledge of the object operating in wide-field mode, so it does not need time-consuming raster scanning. Besides a general improvement of the image quality at a fixed number of photons irradiated through the object, we demonstrate a clear reduction of the uncertainty in the quantitative phase estimation. Significant application, in particular in biology, can be envisaged. [1] M.Genovese, J.of Optics, 18 (2016) 073002 [2] G.Brida et al., Nat.Phot. 4, 227 (2010). N.Samantaray et al. Light: Sc.&App.(2017) 6, e17005 [3] E.Lopaeva et al.,PRL 110, 153603 (2013)