Istituto Nazionale di Ricerca Metrologica
METRICA Archivio istituzionale della ricerca - INRIMNot a member yet
8322 research outputs found
Sort by
Time Metrology for Fundamental Physics Experiments: INRIM’s experience with the FRATERNISE project
No full textFlexible Physical Unclonable Functions Based on Non-deterministically Distributed Dye-Doped Fibers and Droplets
No full textThe development of new anticounterfeiting solutions is a constant challenge and involves several research fields. Much interest is currently devoted to systems that are impossible to clone, based on the physical unclonable function (PUF) paradigm. In this work, a new strategy based on electrospinning and electrospraying of dye-doped polymeric materials is presented for the manufacturing of flexible free-standing films that embed simultaneously different PUF keys. The proposed films can be used to fabricate novel anticounterfeiting labels having three encryption levels: (i) a map of fluorescent polymer droplets, with random positions on a dense yarn of polymer nanofibers, (ii) a characteristic fluorescence spectrum for each label, and (iii) the unique speckle patterns that every label produces when illuminated with coherent laser light shaped in different wavefronts. The intrinsic uniqueness introduced by the manufacturing process encodes enough complexity into the optical anticounterfeiting tag to generate thousands of cryptographic keys. The simple and cheap fabrication process as well as multilevel authentication makes such colored polymeric unclonable tags a practical solution in the secure protection of goods in our daily life
Characterization of surface finiture of different steels on mechanical components for energy harvesting
Get PDFTime-resolved depolarization analysis of back-scattered light
Get PDFStudying the depolarization rate of light emerging from a turbid medium holds promise for the non-invasive characterization of its single-scattering properties, with relevant application in the quality analysis of different specimens or for diagnostic purposes in the biomedical field, to name a few. However, irrespective of sample geometry, the dynamics of light depolarization takes place on a time scale of few ps, which is too fast for traditional detection methods. Here, we present experimental results on the time-domain evolution of the depolarization ratio of light that is diffusely reflected from a scattering medium, using linearly polarized fs pulses in an all-optical gating scheme. Time-resolved reflectance curves are recorded in the parallel and perpendicular polarization channels relative to the illumination beam, granting direct access to the depolarization rate. We demonstrate our experimental approach on a lipid emulsion, fitting the data with a polarized Monte Carlo simulation to retrieve the average particle size and scattering asymmetry factor using just two time-domain reflectance measurements in a semi-infinite geometry
Assessment of the feasibility of breast lesion detection with contrast source inversion for microwave tomography: a virtual experiment
No full textIn this paper, the microwave tomography performed using the contrast source inversion method was investigated. A two-dimensional model problem, composed of a cylindrical phantom positioned at the center of the receiving antennas' circular distribution, provided the setup for virtual experiments. Both a homogeneous phantom, with electrical properties that approximate the ones of a dense breast, and several heterogeneous phantoms, with an inclusion whose high electrical properties simulate those of a breast lesion, were considered. The effect of the initial guess on the reconstruction of the homogeneous phantom was assessed for a first investigation. Then, the detectability of the inclusion in the heterogeneous phantom was tested varying its size, position, and electrical properties. Results suggested that a priori information is useful to build a robust initial guess. The inclusion was detectable in the permittivity maps independently of the considered dimension and position, whereas structured noise was predominant in the conductivity maps
Phase Noise in Real-World Twin-Field Quantum Key Distribution
Get PDFThe impact of noise sources in real-world implementations of twin-field quantum key distribution (TF-QKD) protocols is investigated, focusing on phase noise from photon sources and connecting fibers. This work emphasizes the role of laser quality, network topology, fiber length, arm balance, and detector performance in determining key rates. Remarkably, it reveals that the leading TF-QKD protocols are similarly affected by phase noise despite different mechanisms. This study demonstrates duty cycle improvements of over a factor of two through narrow-linewidth lasers and phase-control techniques, highlighting the potential synergy with high-precision time and frequency distribution services. Ultrastable lasers, evolving toward integration and miniaturization, offer promising solutions for agile TF-QKD implementations on existing networks. Properly addressing phase noise and practical constraints allows for consistent key rate predictions, protocol selection, and layout design, crucial for establishing secure long-haul links for the quantum communication infrastructures under development in several countries.This study explores the impact of various noise sources on twin-field quantum key distribution (TF-QKD) systems, focusing on phase noise from photon sources and fibers. Results show that different TF-QKD protocols are similarly affected by phase noise. Techniques like using ultrastable lasers and phase stabilization can double key rates, promising secure long-distance quantum communication infrastructures. imag
Activation of telecom emitters in silicon upon ion implantation and ns pulsed laser annealing
Get PDFRecent demonstrations of optically active telecom emitters show that silicon is a compelling candidate for solid-state quantum photonic platforms. In particular, the fabrication of a defect known as the G center has been shown in carbon-rich silicon upon conventional thermal annealing. However, the high-yield controlled fabrication of these emitters at the wafer scale still requires the identification of a suitable thermodynamic pathway enabling its activation following ion implantation. Here we demonstrate the activation of G centers in high-purity silicon substrates upon nanosecond pulsed laser annealing. The proposed method enables non-invasive, localized activation of G centers by the supply of short non-stationary pulses, thus overcoming the limitations of conventional rapid thermal annealing related to the structural metastability of the emitters. A finite-element analysis highlights the strong non-stationarity of the technique, offering radically different defect-engineering capabilities with respect to conventional longer thermal treatments, paving the way to the direct and controlled fabrication of emitters embedded in integrated photonic circuits and waveguides