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The processes of heat transfer occurring between the Earth’s asthenosphere and lithosphere are responsible for partial melting of rocks, leading to the magma generation and its migration and segregation in the crust and, possibly, to volcanoes generation at the surface. Convection is the dominant mechanism regulating the heat transfer from the asthenosphere to the lithosphere, although many aspects of the whole process are not yet clear. Therefore, the knowledge of the physical processes leading to the melting of the lithospheric rocks has important consequences in understanding the interior Earth dynamics, the surface volcanic dynamics, and its related hazards. Rock melting occurs when the temperature gradient meets the rock solidus. Here, we propose a nonlinear convective 1D analytical model (representing an approximation of more 3D complex models). The steady-state solution of our equation is in good agreement with the estimated geotherms of the asthenosphere. A perturbative approach leads to a heat swelling at the boundary between asthenosphere and lithosphere able to determine its melting and the birth of a volcano.

We investigate the accuracy and precision of triaxial dynamical orbit models by fitting 2D mock observations of a realistic N-body merger simulation resembling a massive early-type galaxy with a supermassive black hole. We show that we can reproduce the triaxial N-body merger remnant’s correct black hole mass, stellar mass-to-light ratio and total enclosed mass (inside the half-light radius) for several different tested orientations with an unprecedented accuracy of 5–10 per cent. Our dynamical models use the entire non-parametric line-of-sight velocity distribution (LOSVD) rather than parametric LOSVDs or velocity moments as constraints. Our results strongly suggest that state-of-the-art integral-field projected kinematic data contain only minor degeneracies with respect to the mass and anisotropy recovery. Moreover, this also demonstrates the strength of the Schwarzschild method in general. We achieve the proven high recovery accuracy and precision with our newly developed modelling machinery by combining several advancements: (i) our new semiparametric deprojection code probes degeneracies and allows us to constrain the viewing angles of a triaxial galaxy; (ii) our new orbit modelling code SMART uses a 5-dim orbital starting space to representatively sample in particular near-Keplerian orbits in galaxy centres; (iii) we use a generalized information criterion AICp to optimize the smoothing and to compare different mass models to avoid biases that occur in χ2-based models with varying model flexibilities.

European physical journal special topics 229(24), 3675 - 4284 (2020). doi:10.1140/epjst/e2020-000127-8, This report presents the conceptual design of a new European research infrastructure EuPRAXIA. The concept has been established over the last four years in a unique collaboration of 41 laboratories within a Horizon 2020 design study funded by the European Union. EuPRAXIA is the first European project that develops a dedicated particle accelerator research infrastructure based on novel plasma acceleration concepts and laser technology. It focuses on the development of electron accelerators and underlying technologies, their user communities, and the exploitation of existing accelerator infrastructures in Europe. EuPRAXIA has involved, amongst others, the international laser community and industry to build links and bridges with accelerator science — through realising synergies, identifying disruptive ideas, innovating, and fostering knowledge exchange. The Eu-PRAXIA project aims at the construction of an innovative electron accelerator using laser- and electron-beam-driven plasma wakefield acceleration that offers a significant reduction in size and possible savings in cost over current state-of-the-art radiofrequency-based accelerators. The foreseen electron energy range of one to five gigaelectronvolts (GeV) and its performance goals will enable versatile applications in various domains, e.g. as a compact free-electron laser (FEL), compact sources for medical imaging and positron generation, table-top test beams for particle detectors, as well as deeply penetrating X-ray and gamma-ray sources for material testing. EuPRAXIA is designed to be the required stepping stone to possible future plasma-based facilities, such as linear colliders at the high-energy physics (HEP) energy frontier. Consistent with a high-confidence approach, the project includes measures to retire risk by establishing scaled technology demonstrators. This report includes preliminary models for project implementation, cost and schedule that would allow operation of the full Eu-PRAXIA facility within 8—10 years., Published by Springer, Heidelberg

We show that infrared radiation impinging onto a one-dimensional array of grooves drilled in the superconductor electrode of a long overlap junction can improve matching between fluxon oscillations at THz frequencies and a spoof plasmon of comparable wavelength. This example proves that metamaterials can be very helpful in integrating superconductive and subwavelength optical circuits with optimized matching, bridging the gap between infrared and microwave radiation.

Figure 20.1 was not correct in the published article. The original article has been corrected. The published apologizes for the inconvenience.

Following on from our recent work, we investigate a stochastic approach to non-equilibrium quantum spin systems. We show how the method can be applied to a variety of physical observables and for different initial conditions. We provide exact formulae of broad applicability for the time-dependence of expectation values and correlation functions following a quantum quench in terms of averages over classical stochastic processes. We further explore the behavior of the classical stochastic variables in the presence of dynamical quantum phase transitions, including results for their distributions and correlation functions. We provide details on the numerical solution of the associated stochastic differential equations, and examine the growth of fluctuations in the classical description. We discuss the strengths and limitations of the current implementation of the stochastic approach and the potential for further development., v1: 14 + 7 pages, 16 figures. v2: accepted version, minor changes

25th International Conference on the Application of Accelerators in Research and Industry, CAARI 2018, Texas, USA, 12 Aug 2018 - 17 Aug 2018; AIP conference proceedings 2160(1), 040012-1 - 040012-9 (2019). doi:https://doi.org/10.1063/1.5127692, Plasma accelerators present one of the most suitable candidates for the development of more compact particle acceleration technologies, yet they still lag behind radiofrequency (RF)-based devices when it comes to beam quality, control, stability and power efficiency. The Horizon 2020-funded project EuPRAXIA (“European Plasma Research Accelerator with eXcellence In Applications”) aims to overcome the first three of these hurdles by developing a conceptual design for a first international user facility based on plasma acceleration. In this paper we report on the main features, simulation studies and potential applications of this future research infrastructure., Published by AIP Publishing, Melville, NY

Background: Despite the dominance of respiratory disease, acute-on-chronic liver failure (ACLF) and acute decompensation (AD) have been reported in patients with COVID-19 and preexisting liver disease, in particular cirrhosis. Moreover, COVID-19 has been associated with increased mortality in patients with end-stage liver disease (ESLD). Aim our study is to evaluate the impact of SARS-CoV-2 infection in patients with ESLD listed for liver transplant (LT). Methods: Data from adults listed for LT with laboratory-confirmed SARS-CoV-2 infection were collected from 7 LT centers across Italy. Results: From March 1st to October 31st 2020, 29 patients listed for LT were tested positive for SARS-CoV-2 infection. Twenty-one patients (72%) were male, median age was 59 years (20-71). The most common indication (70%) for LT was ESLD. The mean MELD score was 18 (8-32). At diagnosis, twenty patients (69%) presented at least one symptom: 38% fever, 28% dry cough, and 31% respiratory distress. Notably, 25% of patients presented hepatic encephalopathy as first presenting symptom. The remaining 9 patients (31%) were completely asymptomatic: nasopharyngeal swab was performed according to surveillance protocols. Twenty-one patients (70%) required hospitalization for the management of COVID-19. Respiratory support was necessary in 13 patients (45%): 5 (17%) required O2-supply, 4 (14%) non-invasive ventilation and 4 (14%) mechanical ventilation. Only five patients (17%) received at least one drug for infection treatment (see table). Heparin was administrated in 7 patients (28%). No bleeding episodes were reported. Eight (%) patients died after a median time of 6 days (2-29) from Covid-19 diagnosis, with a 30-day-mortality rate of 30%. Three patients died of liver failure, while the remaining of multiple organ failures. In the univariate analysis, factors associated with 30-days mortality were respectively presence of comorbidities (0.07), severity of liver disease according to MELD score (0.05) and severity of respiratory failure (0.011). In the cox-regression analysis, only the severity of respiratory failure was significantly associated with the mortality (HR 3.13, IC 1.53-6.3). Conclusions: COVID-19 is associated with elevated mortality in LT candidates, listed for ESLD.

A numerical investigation on the spatiotemporal evolution of an electron beam, externally injected in a plasma in the presence of a plasma wake field, is carried out. The latter is driven by an ultra-short relativistic axially-symmetric femtosecond electron bunch. We first derive a novel Poisson-like equation for the wake potential where the driving term is the ultra-short bunch density, taking suitably into account the interplay between the sharpness and high energy of the bunch. Then, we show that a channel is formed longitudinally, through the externally injected beam while experiencing the effects of the bunch-driven plasma wake field, within the context of thermal wave model. The formation of the channel seems to be a final stage of the 3D evolution of the beam. This involves the appearance of small filaments and bubbles around the longitudinal axis. The bubbles coalesce forming a relatively stable axially-symmetric hollow beam structure., 6 pages, 9 figures

Within the framework of the Vlasov–Maxwell system of equations, we describe the self-consistent interaction of a relativistic charged-particle beam with the surroundings while propagating through a plasma-based acceleration device. This is done in terms of the concept of coupling (longitudinal) impedance in full analogy with the conventional accelerators. It is shown that also here the coupling impedance is a very useful tool for the Nyquist-type stability analysis. Examples of specific physical situations are finally illustrated.

We investigate a stochastic approach to non-equilibrium quantum spin systems based on recent insights linking quantum and classical dynamics. Exploiting a sequence of exact transformations, quantum expectation values can be recast as averages over classical stochastic processes. We illustrate this approach for the quantum Ising model by extracting the Loschmidt amplitude and the magnetization dynamics from the numerical solution of stochastic differential equations. We show that dynamical quantum phase transitions are accompanied by clear signatures in the associated classical distribution functions, including the presence of enhanced fluctuations. We demonstrate that the method is capable of handling integrable and non-integrable problems in a unified framework, including those in higher dimensions., 5 pages, 5 figures

Pd(0) is able to catalyze oxygen-involving reactions because of its capability to convert molecular oxygen to the very reactive atomic form. Consequently, the embedding of a little amount of Pd(0) clusters in polymeric phases can be technologically exploited to enhance the incineration kinetic of these polymers. The effect of nanostructuration on the Pd(0) catalytic activity in the polymer incineration reaction has been studied using poly(N-vinyl-2-pyrrolidone) (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \overline{Mw} $$\end{document}Mw¯ = 10,000 gmol−1) as polymeric model system. A change in the PVP incineration kinetic mechanism with significant increase in the reaction rate was experimentally found. The kinetic of the Pd(0)-catalyzed combustion has been studied by isothermal thermogravimetric analysis. After a short induction time, the combustion in presence of Pd(0) clusters shifted to a zero-order kinetic from a second-order kinetic control, which is operative in pure PVP combustion reaction. In addition, the activation energy resulted much lowered compared to the pure PVP incineration case (from 300 to 260 kJ/mol).

Recently a new injection scheme for Laser Wake Field Acceleration, employing a single 100-TW-class laser system, has been proposed. In the Resonant Multi-Pulse Ionization injection (ReMPI) a resonant train of pulses drives a large amplitude plasma wave that traps electrons extracted from the plasma by further ionization of a high-Z dopant (Argon in the present paper). While the pulses of the driver train have intensity below the threshold for the dopant's ionization, the properly delayed and frequency doubled (or more) ionization pulse possesses an electric field large enough to extract electrons, though its normalized amplitude is well below unity. In this paper we will report on numerical simulations results aimed at the generation of GeV-scale bunches with normalized emittance and {\it rms} energy below $80\, nm \times rad $ and $0.5\, \%$, respectively. Analytical consideration of the FEL performance for a $1.3\, GeV$ bunch will be also reported., EAAC 2017 Conference, Elba, Italy

In microscopy high magnifications are achievable for investigating micro-objects but the paradigm is that higher is the required magnification lower the depth of focus is. For an object having a 3D complex shape only a portion of it appears in well focus to the observer that essentially is looking at a single image plane. If an accurate analysis of the whole object has to be performed it is necessary to have a single sharp image in which all details of the object. We propose an holographic microscope to construct an EFI without any mechanical scanning or special optical components. We demonstrate that by this novel approach using DH it is possible to obtain EFI of a 3D object without any mechanical scanning. It will be shown that the unique property in DH, that the phase information of the reconstructed wave front is available numerically allows to construct an EFI image of the object without mechanical movement and by a single image. The proposed microscope could be useful to conduct investigation for experiments in microgravity conditions.

A theoretical investigation of the propagation of a relativistic electron (or positron) particle beam in an overdense magnetoactive plasma is carried out within a fluid plasma model, taking into account the individual quantum properties of beam particles. It is demonstrated that the collective character of the particle beam manifests mostly through the self-consistent macroscopic plasma wakefield created by the charge and the current densities of the beam. The transverse dynamics of the beam–plasma system is governed by the Schrödinger equation for a single-particle wavefunction derived under the Hartree mean field approximation, coupled with a Poisson-like equation for the wake potential. These two coupled equations are subsequently reduced to a nonlinear, non-local Schrödinger equation and solved in a strongly non-local regime. An approximate Glauber solution is found analytically in the form of a Hermite–Gauss ring soliton. Such non-stationary (‘breathing’ and ‘wiggling’) coherent structure may be parametrically unstable and the corresponding growth rates are estimated analytically.

Different strategies of DAAs treatment are currently possible both pre- and postliver transplantation (LT). Clinical and economic consequences of these strategies still need to be adequately investigated; this study aims at assessing their cost-effectiveness. A decision analytical model was created to simulate the progression of HCV-infected patients listed for decompensated cirrhosis (DCC) or for hepatocellular carcinoma (HCC). Three DAAs treatment strategies were compared: (i) a 12-week course of DAAs prior to transplantation (PRE-LT), (ii) a 4-week course of DAAs starting at the time of transplantation (PERI-LT) and (iii) a 12-week course of DAAs administered at disease recurrence (POST-LT). The population was substratified according to HCC presence and, in those without HCC, according to the MELD score at listing. Data on DAAs effectiveness were estimated using a cohort of patients still followed by 11 transplant centres of the European Liver and Intestine Transplant Association and by data available in the literature. In this study, PRE-LT treatment strategy was dominant for DCC patients with MELD20 and for those with HCC. Sensitivity analyses confirmed PRE-LT as the cost-effective strategy for patients with MELD≤20. In conclusion, PRE-LT treatment is cost-effective for patients with MELD≤20 without HCC, while treatments after LT are cost-effective in cirrhotic patients with MELD>20 and in those with HCC. It is worth reminding, though, that the final choice of a specific regimen at the patient level will have to be personalized based on clinical, social and transplant-related factors

This paper deals with the design of coded waveforms which optimize radar performances in the presence of colored Gaussian disturbance. We focus on the class of phase coded pulse trains and determine the radar code which approximately maximizes the detection performance under a similarity constraint with a prefixed radar code. This is tantamount to forcing a similarity between the ambiguity functions of the devised waveform and of the pulse train encoded with the prefixed sequence. We consider the cases of both continuous and finite phase alphabet, and formulate the code design in terms of a nonconvex, NP-hard quadratic optimization problem. In order to approximate the optimal solutions, we propose techniques (with polynomial computational complexity) based on the method of semidefinite program (SDP) relaxation and randomization. Moreover, we also derive approximation bounds yielding a ldquomeasure of goodnessrdquo of the devised algorithms. At the analysis stage, we assess the performance of the new encoding techniques both in terms of detection performance and ambiguity function, under different choices for the similarity parameter. We also show that the new algorithms achieve an accurate approximation of the optimal solution with a modest number of randomizations.

We propose and experimentally demonstrate an active two-dimensional (2D) 12-fold photonic quasi crystal (PQC) which consists of air rods in a nanocomposite prepared by incorporating CdSe/CdS core/shell nanorods (NR) in a polymer. The effect of aperiodic order on the diffraction pattern was observed by measuring the far field diffraction pattern of the 2D-12 fold active PQC and investigated by analytical calculation of the theoretical Fourier spectrum. Light extraction has been found to occur via the band edge mode and to follow the dispersion properties of the dodecagonal structure. Finite-difference time-domain (FDTD) was used to calculate Bragg extracted light spectrum and compare the results of the numerical simulations with the experimental emission spectrum. The dispersion properties of the structure were also analyzed by theoretical band calculations and confirmed the presence of a resonance peak at 628 nm with a full width at half-maximum of 20 nm. Our results may provide useful tools for the design and optimization of novel photonic devices for light emitting applications. © 2014 by American Scientific Publishers.

This paper deals with the design of coded waveforms which optimize radar performances in the presence of colored Gaussian disturbance. We focus on the class of linearly coded pulse trains and determine the optimum radar code according to the following criterion: maximization of the detection performance under a control on the region of achievable Doppler estimation accuracies, and imposing a similarity constraint with a prefixed radar code. This last constraint is tantamount to requiring a similarity between the ambiguity functions of the devised waveform and of the pulse train encoded with the prefixed sequence. The resulting optimization problem is nonconvex and quadratic. In order to solve it, we propose a technique (with polynomial computational complexity) based on the relaxation of the original problem into a semidefinite program. Thus, the best code is determined through a rank-one decomposition of an optimal solution of the relaxed problem. At the analysis stage, we assess the performance of the new encoding technique in terms of detection performance, region of achievable Doppler estimation accuracies, and ambiguity function.

Istituto di Cibernetica “Eduardo Caianiello” del CNR Comprensorio “A. Olivetti” Fabbr. 70, Via Campi Flegrei 34, I-80078 Pozzuoli (NA), Italy Dipartimento di Scienze Fisiche, Universit`a “Federico II” di Napoli, INFN, Sezione di Napoli, ComplessoUniversitario di M. S. Angelo, Via Cintia, I-80126 Napoli, Italy Lebedev Physical Institute, RAS, Moscow, Russia

We present, for the first time to the best of our knowledge, a phase unwrapping method based on an algorithm which makes use of Green's first identity. This method aims at recovering the correct phase information encoded in a fringe pattern after digital holography (DH) numerical processing. DH provides a quantitative measurement of the three-dimensional surface profile of objects. The information about the profile can be obtained in principle from the phase-map. However, the measured phase-map provides the actual phase values wrapped mod.2π so that an unwrapping process is required in order to reconstruct the object profile.

We introduce a new type of tomographic probability distribution containing complete information about the density matrix (wave function) related to the Fresnel transform of the complex wave function. We elucidate the relation to the symplectic tomographic probability distribution. We present a multimode generalization of the Fresnel tomography and give examples of applications of the present approach. © 2005 Springer Science+Business Media, Inc.

The wave packets, both linear and nonlinear (like solitons) signals described by a complex time-dependent function, are mapped onto positive probability distributions (tomograms). The quasidistributions, wavelets, and tomograms are shown to have an intrinsic connection. The analysis is extended to signals obeying to the von Neumann-like equation. For solitons (nonlinear signals) obeying the nonlinear Schrödinger equation, the tomographic probability representation is introduced. It is shown that in the probability representation the soliton satisfies a nonlinear generalization of the Fokker–Planck equation. Solutions to the Gross–Pitaevskii equation corresponding to solitons in a Bose–Einstein condensate are considered.

Tomographic-probability representation for soliton solutions of Gross-Pitaevskii equation is introduced. Tomograms of the wavefunction describing bright soliton states of Bose-Einstein condensate are obtained in the presence of a quadratic external potential. © EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003.

Carbon nanoscrolls (CNSs) are produced by rolling up the graphite layer in graphite nanoplatelets on a nanofibrous bi-axially oriented polypropylene surface by a shear-friction mechanism. Microstructures of the CNSs are characterized by optical and scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and micro-Raman spectroscopy. Results indicate that the CNSs have a long tubular and fusiform structure with a hollow core surrounded by few graphene layers. The orientation of the graphite lattice with respect to the scroll axis is accurately determined from the split of the vibrational G mode by polarized micro-Raman spectroscopy. Morphological changes produced by the rolling are also described.

An optically transparent nanographite coating has been developed on a poly-methyl methacrylate (PMMA) substrates. The adhesion to the PMMA surface combined with the shear stress allowed an uniform and continuous spreading of the graphite nanocrystals on the substrate surface with formation of a very uniform graphene multilayer coating. This coating is characterized by high piezoresitivity and it is suitable to work as sensible and reliable local strain sensor. Its piezoresistive features have been characterized by bending tests yielding a gauge factor (GF) which is of the order of 50. The structural and strain properties of the compound were studied under stress by infra-red thermography (IRT) and micro-Raman spectroscopy. The strain strength has been estimated as a function of the bending load. The electrical transport was investigated as a function of the applied stress. Features are consistent with an intergrain electrical transport mechanism among graphene platelets.

We present an analytical and numerical study of the interaction of a multi-petawatt, pancake-shaped laser pulse with an unmagnetized plasma. The study has been performed in the ultrarelativistic regime of electron jitter velocities, in which the plasma electrons are almost completely expelled from the pulse region. The calculations are applied to a laser wake field acceleration scheme with specifications that may be available in the next generation of Ti:Sa lasers and with the use of recently developed pulse compression techniques. A set of novel nonlinear equations is derived using a three-timescale description, with an intermediate timescale associated with the nonlinear phase of the electromagnetic wave and with the spatial bending of its wave front. They describe, on an equal footing, both the strong and the moderate laser intensity regimes, pertinent to the core and to the edges of the pulse.

Nowadays, there is a strong interest in carbon nanotubes (CNTs) since these nanostructured materials have large potential applications in different technological fields. In this work, a very simple approach for synthesizing CNTs in mild conditions has been developed and investigated. In particular, the nanotubes have been obtained by thermal defluorination of poly(tetrafluoroethylene) (PTFE) by Si, which also acts as an inorganic catalyst for the CNT growth. Fine powders of PTFE and Si were homogeneously mixed together and then compacted by cold pressing. The obtained composite pills were placed into a quartz tube furnace at 650°C, and a vacuum was applied to remove the gaseous by-product (SiF4). The obtained pyrolysis product consisted of CNTs, wrapping the surface of silicon grains. CNTs have been characterized by scanning electron microscopy, Raman spectroscopy, and large angle x-ray powder diffraction. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 31: 246–251, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21267

We investigate the feedback control of a periodically driven FitzHugh–Nagumo circuit (FHN), which displays both spiking and non-spiking behaviors in chaotic or periodic regimes. The simple high pass filter (washout filter) is compared with an all pass filter which only affects the phase characteristics of the input signal. Experimental measurements performed on the electronic implementation of the FHN are in good agreement with numerical simulations. Apart a small difference in their amplitude corrections that remain in both cases within a few percent with respect to the unperturbed spiking signal, we prove the key role of the phase characteristics of the two filters in achieving control.

We report a numerical method to analyze the fractal characteristics of far-field diffraction patterns for two-dimensional Thue-Morse (2-D TM) structures. The far-field diffraction patterns of the 2-D TM structures can be obtained by the numerical method, and they have a good agreement with the experimental ones. The analysis shows that the fractal characteristics of far-field diffraction patterns for the 2-D TM structures are determined by the inflation rule, which have potential applications in the design of optical diffraction devices.

A correspondence between the families of generalized nonlinear Schrodinger (NLS) equations and generalized KdV equations was recently found using a Madelung fluid description. We similarly consider a special derivative NLS equation. We find a number of solitary waves and periodic solutions (expressed in terms of elliptic Jacobi functions) for a motion with a stationary profile current velocity. We study the stability of a bright solitary wave (ground state) by conjecturing that the Vakhitov-Kolokolov criterion is applicable.

In color digital holography the recording and reconstruction of three holograms, by an optical setup operating in multi-wavelength mode, is necessary. Incorrect superposition of different images at various wavelengths may occur due to the presence of chromatic aberrations. We demonstrate that the compensation of the chromatic aberrations can be achieved by using all of the information contained in the multi-wavelength digital holograms. Chromatic aberration is extracted from phase maps reconstructed at different wavelengths, resulting in perfect full color amplitude reconstructions. The method has important applications in color 3-D holographic imaging and display.

A moireinterferometer is used to measure the thermal expansion of two ferroelectric crystals, LiNbO3 and KTiOPO4. The crystal samples are patterned with a chromium reflective grating and used as a diffractive component in a reflective grating interferometer. The thermal expansion of all the three axes of congruent LiNbO3 and of x and y axes of the flux-grown KTiOPO4 were measured from room temperature to 200 � C. For this temperature range the thermal expansion coefficient has been modeled by a second-order polyno- mial and its coefficients have been estimated by accurate analysis of the resulting moirefringe pattern. � 2007 Elsevier B.V. All rights reserved.

We present an adaptive and dynamic hexagonal electro-optic phase array. The proposed device consists of a 2-dimensional hexagonal array of periodically inverted ferroelectric domains, along the z-axis, in lithium niobate crystals. The phase step is achieved via the application of an external electric field, along the z-axis, through transparent electrodes. Thanks to the electro-optic effect the phase step can changed with continuity over all the 0 to 2π by applying a variable voltage. In this way different patterns can be generated. In fact, one important property of this new proposed configuration of array iluminator is the intrinsic flexibility.

This paper describes the possibility of employing a digital holographic microscope (DHM) to carry out a noncontact and nondestructive characterization of a microheater integrated on a silicon nitride membrane and subjected to a high thermal load. Microheaters can be affected by the presence of the residual stress due to the technological processes appearing in the form of undesired bowing of the membrane. Moreover, when the temperature of the microheater increases, a further warpage of the structure can be induced. A DHM allows for evaluation, with high accuracy, the deformations due to the residual stress and how these deformations are affected by the thermal loads due to the microheater operating mode. In particular, this dynamic analysis is made possible by measuring the unwanted longitudinal displacement induced by the thermal expansion of both the device and its mechanical support. Taking into account this displacement, it is possible to have a continuous monitoring of profile deformation induced by the working condition of the microheater.