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A digital holographic microscope (DHM) is employed as non-invasive metrological tool for inspection and characterization of a micromechanical shunt switches in coplanar waveguide configuration (CPW) for microwave applications. The switch is based on a bridge that can be actuated by using electrodes positioned laterally with respect to the central conductor of the CPW. The DHM features, such as speed, contact-less and non-destructivity, have allowed a full characterization of an electrical actuated shunt switches. In particular, the out-of-plane deformation of the bridge due to the applied voltage has been investigated with high accuracy. DHM inspection allows to investigate the shape of the bridge during the actuation, the total warpage due to the actuation, possible residual gap, possible hysteresis, and so on. These characterizations have been carried out both in static and in dynamic condition. In full paper the complete characterization will be reported together with an accurate description of the optical system employed for the investigation.

A two stage method for allowing direct perfect superimposition and comparison of Fresnel-transform reconstructions of digital holograms recorded at different wavelengths is proposed and demonstrated. The method allows to adjust the size of the reconstruction pixel by varying the reconstruction distance of the first stage. Demonstration is given by superimposing in focus numerical reconstructions of holograms recorded at different wavelengths. The method can be potentially very useful for real-time monitoring in biological processes

In microscopy, high magnifications are achievable for investigating micro-objects but the paradigm is that higher the required magnification, the lower the depth of focus. In this paper we show that it is possible to construct an extended focused image (EFI) image by a coherent optical microscope without any mechanical movement but by using the 3D imaging capability of digital holography (DH). In fact, DH has the unique property of allowing direct calculation and management of an amplitude and phase map along the longitudinal direction in front of the digital camera. That constitutes a fundamental feature of DH to construct an EFI image of an object or systems experiencing dynamic evolution since the recording of only one image is needed instead of performing a mechanical scanning and to record several images at different focus planes. In other words, by means of this approach it is possible to obtain an EFI image for studying dynamic objects, such as biological objects, dynamic MEMS

A novel broad-band telecom laser source is used to realize a lateral-shear scanning-wavelength interferometer for measuring the thickness of thin plates. We show that the wide tunability range allows to detect samples down to tens of microns with a relative uncertainty of less than 0.5% and a resolution of about 1 nm. A comparable accuracy in the thickness characterization of double-layer structures is also demonstrated. In turn, the wide tunability range needs the dispersion law of the materials to be taken into account in the model for correct thickness evaluation.

Digital holograms recorded with a charge-coupled device array are numerically reconstructed in amplitude and phase through calculation of the Fresnel-Kirchhoff integral. The flexibility offered by the reconstruction process in digital holography allows exploitation of new possibilities of application in microscopy. Through the reconstruction process we will show that it is possible to control image parameters as focus distance, image size, and image resolution. Those explored potentialities open further the novel prospective of application of digital holography in single- and multiwavelengths operation either for display or metrological applications. We demonstrate the concept of controlling parameters in image reconstruction of digital holograms in some real situations for inspecting silicon microelectronic-mechanical systems structures.

Tomographic-probability representation for ssoliton solutions of Gross-Pitaevskii equation is introduced. tomograms of the wavefunction describing bright soliton states of Bose-Einstein condensates are obtained in the presence of a quadratic external potential

An electro-optic device applied as an optical beam deflector and switch at different wavelengths has been built and tested. The electro-optic device is based on domain-engineered lithium niobate (LiNbO3). In this paper, for the first time, its operation has been visualized by an imaging camera. The device has been characterized both at the visible wavelength (632.8 nm) and at a typical telecom wavelength (1532 nm). Furthermore, the device has been tested as an amplitude modulator in the mid-infrared region as well, at a wavelength of similar to4.3 mum, where no Pockels cells are available. A detailed description of this device is given, and the experimental results are discussed.

The longitudinal shift caused by a sample interposed in the object arm of an interferometric-holographic configuration is determined from the Fresnel-based numerical reconstruction of the digitezed hologram

It is developed a tomographic representation of wavefunctions which are solutions of the generalized nonlinear Schrodinger equation and it is discussed its connection with the Weyl-Wigner map. examples of symplectic tomography and Fresnel tomography of linear and nonlinear signals are presented and discussed

We investigate digital holography method as metrological tool for inspection and characterization of MEMS structures. The efficiency of the digital holography is demonstrated measuring out of plane deformations due to the intrinsic residual stress. Microstructures under investigation are of two different types: the first are made of a single polysilicon layer, whereas the second are bimorph structures with a thin silicon nitride layer over the polysilicon one. These structures exhibit an out-of-plane deformation owing to residual stresses between the different layers. The characterization of these deformations is instrumental to study and understand the effect of residual stress on the deformation of the single microstructures. To this aim digital holography has been applied as metrological tool in order to obtain the profile of the microstructures. These data are employed in analytical and numerical model to evaluate residual stress inside the investigated structures. Moreover, digital holography has been employed to evaluate MEMS behavior when subjected to thermal load. Profile of cantilevers, with dimensions from 1 to 50 µm, has been measured

We realized one and two dimensional periodic ferrolectric domain structurure obtained by an electric- field poling process applied to 500 microns thick lithium niobate crystal samples patterned by means interference litography

Morphology of MEMS structures subjected to static deformations and thermal loading are investigated by digital microscope holography

We propose the use of digital holography as a metrological tool for inspection and characterization of MEMS structures. We show that DH can be efficiently employed to assess the fabbrication process of microstructures as well as to test their behaviour in operative conditions.DH allows reconstructing amplitude and phase of microscopic objects and, compared to traditional microscopy, it provides quantitative phase dtermination

We describe an infrared interferometric technique based on a two-dimensional spatial fringe analysis Fourier method for investigating the characteristic ring diffraction pattern generated by the self-phase-modulation effect induced in nematic liquid crystals (NLCs) by an infrared laser beam and for measuring the nonlinear refractive index of the NLCs. The experimental setup employs a Mach-Zehnder interferometer with a cw CO2 laser emitting at 10.6 mum and a pyroelectric optoelectronic sensor matrix to detect the modulated ring-pattern intensity distribution formed in the far field by a nematic E7 sample. A Fourier-transform-based analysis of the interference fringe pattern allows comparison of the measurements with the theoretical ring-pattern intensity distribution. We show that accurate determination of the nonlinear refractive index can be obtained by analyzing the two-dimensional phase distribution of the modulated ring pattern.

An analitical approach is developed that allows for computing the time resolved transmittance signal through a slab of turbid material in presence of spatially varying Gaussian absorptive inhomogeneity included in thescattering slab.The perturbed time-resolved signal is calculated in the framework of the diffusion approximation up to the first order correction in the relative degree of the absrptive perturbation parameter. Numerical FEM simulations arecompared with the prediction of the perturbation-based approach for different values of the optical coefficients of the inhomogeneity and of the host medium and for different size of the inclusion

Ferroelectric domain micro structuring of bulk lithium Niobate is very useful for optoelectronic applications such as non-linear optic employing Quasi-Phase-Matching for efficient harmonic and parametric conversion processes. We report on the application of digital holography as metrological tol for the inspection and characterization of the domain structures in bulk lithium niobate samples

An interferometric method is proposed, that can be used to measure simultaneously the thickness and the refractive index of thin films. The experimental set-up employies a lateral-shear interferometer and a DFB laser to scan across the wavelength range

A digital holographic technique is used for correcting pahse aberrations errors via numerical reconstruction of digitally recorded holograms

We report on an Mach-Zehnder interferometric technique for characterizing uniaxial crystals. The technique is used for characterizing lithium niobate crystal plates and for measuring its principal refractive indices

The reflecting grating interferometer is a folded and reversal wave-front interferometer sensitive only to asymmetrical aberrations such as third-order come. The RGI can isolate and evaluate coma both in nearly collimated and in noncollimated beams. We propose a RGI with a different optical configuration that includes a lateral shearing in addition to folding and reversal operations. Optical path difference equations for interpreting interferograms and numerical simulations are presented to show how the interferometer works in the shearing configuration. Its potential applications are described and discussed.

Digitaly holography is shown to be an efficient technique for 3D shape measurements of MEMS with submicron accuracy. Both phase and amplitude images can be numerically reconstruceted to obtain the 3D defoemation map of the microelectronic structure under test. The principle of the method is described and several examples of numerical reconstruction are shown

We report a new interferometric technique for measuring the ordinary and extraordinary refractive indices of uniaxial crystals. The technique is based on the measurement of the rotation-dependent phase changes of the optical path length in crystal plates. Accurate measurement of the phase shift as a function of the rotation of the sample is achieved by using a fast-Fourier-transform based fringe analysis method for phase retrieval. The principle of the method is discussed and measurements of the ordinary and extraordinary refractive indices of a lithium niobate crystal are reported.

A classical description of the dynamics of a dissipative charged-particle fluids in a quadrupole- like device is developed. It is shown that the set of the classical fluid equations contains the same information as a complex function satisfying a Scrodinger-like equantions in which the Planck's constant is replaced by the time-varying emittance, which is related to the time-varying temperature of the fluid. . Within this framework the dynamics of an electron bunch in a storage ring in the presence of radiation damping and quantum exication is recovered.