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Carlo Magro

Bio: Carlo Magro is an academic researcher from STMicroelectronics. The author has contributed to research in topics: Digital holography & Holographic interferometry. The author has an hindex of 5, co-authored 11 publications receiving 478 citations.

Papers
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Journal ArticleDOI
TL;DR: An approach is proposed for removing the wavefront curvature introduced by the microscope imaging objective in digital holography, which otherwise hinders the phase contrast imaging at reconstruction planes and it is shown that a correction effect can be obtained at all reconstruction planes.
Abstract: An approach is proposed for removing the wave front curvature introduced by the microscope imaging objective in digital holography, which otherwise hinders the phase contrast imaging at reconstruction planes. The unwanted curvature is compensated by evaluating a correcting wave front at the hologram plane with no need for knowledge of the optical parameters, focal length of the imaging lens, or distances in the setup. Most importantly it is shown that a correction effect can be obtained at all reconstruction planes. Three different methods have been applied to evaluate the correction wave front and the methods are discussed in detail. The proposed approach is demonstrated by applying digital holography as a method of coherent microscopy for imaging amplitude and phase contrast of microstructures.

406 citations

Proceedings ArticleDOI
07 Nov 2002
TL;DR: Digital holography is proposed as a non-contact method for the inspection and characterization of MEMS and can be useful for assessing the fabrication process and the functionality as well as the reliability of micromachined structures.
Abstract: Digital holography is proposed as a non-contact method for the inspection and characterization of MEMS. The method can be useful for assessing the fabrication process and the functionality as well as the reliability of micromachined structures.

33 citations

Journal ArticleDOI
TL;DR: The high sensitivity of the proposed method enables us to precisely determine the structure morphology and calculate the intrinsic stress and bending moment, in good agreement with an analytical model, and can be exploited to assess the fabrication process and the functionality as well as the reliability of micromachined structures.
Abstract: Microelectromechanical systems (MEMS) are integrated microdevices or systems combining electrical and mechanical components that can sense, control, and actuate on the microscale and function individually or in arrays to generate effects on the macroscale. MEMS is one of the most promising areas in future computers and machinery, the next logical step in the silicon revolution. Fabricated using integrated circuit (IC)-compatible batch-processing technologies, the small size of MEMS opens a new line of exciting applications, including aerospace, automotive, biological, medical, fluidics, military, optics, and many other areas. We explore the potentialities of a high-resolution optical technique for characterizing MEMS microstructures. The method is based on the application of digital holography as a noncontact metrological tool for inspection and characterization of the microstructure surface morphology. The microstructures under investigation are homogeneous and bimorph polysilicon cantilevers; both structures exhibit an out-of-plane deformation owing to residual stress. The high sensitivity of the proposed method enables us to precisely determine the structure morphology and calculate the intrinsic stress and bending moment, in good agreement with an analytical model. Hence, the proposed technique can be exploited to assess the fabrication process and the functionality as well as the reliability of micromachined structures. Moreover, it is also used as a tuning tool for design and finite-element-based simulation software.

21 citations

Proceedings ArticleDOI
24 Mar 2003
TL;DR: In this article, the use of digital holography (DH) as a metrological tool for inspection and characterization of MEMS structures was proposed, which can be efficiently employed to assess the fabrication process of micro structures as well as to test their behaviour in operative conditions.
Abstract: We propose the use of digital holography (DH) as a metrological tool for inspection and characterization of MEMS structures. We show that DH can be efficiently employed to assess the fabrication process of micro structures as well as to test their behaviour in operative conditions. DH allows reconstructing both the amplitude and phase of microscopic objects and, compared to traditional microscopy, it provides quantitative phase determination. We demonstrate that DH allows determination of full field deformation maps that can be compared with analytical and/or numerical models of the deformed microstructure. Application of DH on structures with several different geometries and shapes, like cantilever beams, bridges and membranes is reported and result will be discussed. Dimensions of the inspected microstructures ranging from 1 to 50µm. Examples of application are presented were DH allows determination with high accuracy out of plane deformations due to the residual stress introduced by the fabrication process. An optical set-up for recording digital holograms based on a Mach-Zehnder interferometer was adopted and a laser source which wavelength is =532 nm was employed. The light reflected by the object under investigation was made to interfere with a plane wave front. Holograms were recorded by a CCD array with 1024 x 1280 square pixels with 6.7 µm size. A mirror mounted on a piezo-actuator was inserted along the reference arm of the interferometric in order to introduce controlled phase steps and to employ phase shifting technique. This technique allows suppressing both the zeroth-order and the conjugate wave-front in the numerical holographic reconstruction process. A method for compensating numerically curvature of the wave front and introduced by the microscopic objective lens is proposed and discussed. Keywords: Digital Holography, Interferometry, MEMS characterization.

21 citations

Patent
03 Apr 2012
TL;DR: In this article, a galvanic-isolated coupling of circuit portions is accomplished on the basis of a stacked chip configuration, which can be fabricated on any appropriate process technology, thereby incorporating one or more coupling elements, such as primary or secondary coils of a micro transformer, wherein the final characteristics of the micro transformer are adjusted during the wafer bond process.
Abstract: A galvanic-isolated coupling of circuit portions is accomplished on the basis of a stacked chip configuration. The semiconductor chips thus can be fabricated on the basis of any appropriate process technology, thereby incorporating one or more coupling elements, such as primary or secondary coils of a micro transformer, wherein the final characteristics of the micro transformer are adjusted during the wafer bond process.

17 citations


Cited by
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Journal ArticleDOI
TL;DR: Digital holography is an emerging field of new paradigm in general imaging applications as discussed by the authors, and a review of a subset of the research and development activities in digital holographic microscopy techniques and applications is presented.
Abstract: Digital holography is an emerging field of new paradigm in general imaging applications. We present a review of a subset of the research and development activities in digital holography, with emphasis on microscopy techniques and applications. First, the basic results from the general theory of holography, based on the scalar diffraction theory, are summarized, and a general description of the digital holographic microscopy process is given, including quantitative phase microscopy. Several numerical diffraction methods are described and compared, and a number of representative configurations used in digital holography are described, including off-axis Fresnel, Fourier, image plane, in-line, Gabor, and phase-shifting digital holographies. Then we survey numerical techniques that give rise to unique capabilities of digital holography, including suppression of dc and twin image terms, pixel resolution control, optical phase unwrapping, aberration compensation, and others. A survey is also given of representative application areas, including biomedical microscopy, particle field holography, micrometrology, and holographic tomography, as well as some of the special techniques, such as holography of total internal reflection, optical scanning holography, digital interference holography, and heterodyne holography. The review is intended for students and new researchers interested in developing new techniques and exploring new applications of digital holography.

672 citations

Journal ArticleDOI
TL;DR: Digital holographic microscopy enables a quantitative phase contrast metrology that is suitable for the investigation of reflective surfaces as well as for the marker-free analysis of living cells.
Abstract: Digital holographic microscopy enables a quantitative phase contrast metrology that is suitable for the investigation of reflective surfaces as well as for the marker-free analysis of living cells. The digital holographic feature of (subsequent) numerical focus adjustment makes possible applications for multifocus imaging. An overview of digital holographic microscopy methods is described. Applications of digital holographic microscopy are demonstrated by results obtained from livings cells and engineered surfaces.

668 citations

Journal ArticleDOI
TL;DR: Techniques of digital holography are improved in order to obtain high-resolution, high-fidelity images of quantitative phase-contrast microscopy, and the angular spectrum method of calculating holographic optical field is seen to have significant advantages including tight control of spurious noise components.
Abstract: Techniques of digital holography are improved in order to obtain high-resolution, high-fidelity images of quantitative phase-contrast microscopy. In particular, the angular spectrum method of calculating holographic optical field is seen to have significant advantages including tight control of spurious noise components. Holographic phase images are obtained with 0.5 μm diffraction-limited lateral resolution and largely immune from the coherent noise common in other holographic techniques. The phase profile is accurate to about 30 nm of optical thickness. Images of SKOV-3 ovarian cancer cells display intracellular and intranuclear organelles with clarity and quantitative accuracy.

651 citations

Journal ArticleDOI
TL;DR: An approach is proposed for removing the wavefront curvature introduced by the microscope imaging objective in digital holography, which otherwise hinders the phase contrast imaging at reconstruction planes and it is shown that a correction effect can be obtained at all reconstruction planes.
Abstract: An approach is proposed for removing the wave front curvature introduced by the microscope imaging objective in digital holography, which otherwise hinders the phase contrast imaging at reconstruction planes. The unwanted curvature is compensated by evaluating a correcting wave front at the hologram plane with no need for knowledge of the optical parameters, focal length of the imaging lens, or distances in the setup. Most importantly it is shown that a correction effect can be obtained at all reconstruction planes. Three different methods have been applied to evaluate the correction wave front and the methods are discussed in detail. The proposed approach is demonstrated by applying digital holography as a method of coherent microscopy for imaging amplitude and phase contrast of microstructures.

406 citations

Journal ArticleDOI
TL;DR: A procedure that compensates for phase aberrations in digital holographic microscopy by computing a polynomial phase mask directly from the hologram, which enables one to reconstruct correct and accurate phase distributions, even in the presence of strong and high-order aberration.
Abstract: We present a procedure that compensates for phase aberrations in digital holographic microscopy by computing a polynomial phase mask directly from the hologram. The phase-mask parameters are computed automatically without knowledge of physical values such as wave vectors, focal lengths, or distances. This method enables one to reconstruct correct and accurate phase distributions, even in the presence of strong and high-order aberrations. Examples of applications are shown for microlens imaging and for compensating for the deformations associated with a tilted thick plate. Finally we show that this method allows compensation for the curvature of the specimen, revealing its surface defects and roughness. Examples of applications are shown for microlenses and metallic sphere imaging.

404 citations