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Sanchez-Ortiga E.,University of Valencia | Ferraro P.,Istituto Nazionale di Ottica Applicata | Martinez-Corral M.,University of Valencia | Saavedra G.,University of Valencia | Doblas A.,University of Valencia
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2011

Telecentric architecture is proposed for circumventing, by the pure-optical method, the residual parabolic phase distortion inherent to standard configuration of digital holographic microscopy. This optical circumvention produces several important advantages. Oneis that thereis no need for computer compensation of the parabolic phase during the phase map recovering procedure. The other is that in off-axis configuration, the spatial frequency useful domain is enlarged. The validity of the method is demonstrated by performing quantitative measurement of depth differences with high axial resolution. © 2011 Optical Society of America. Source


Molesini G.,Istituto Nazionale di Ottica Applicata
Optics and Photonics News | Year: 2010

A letter dated December 4, 1643, from Vangelista Torricelli, a lens-maker from Florence, Italy, details the state of the art in 17th century telescope making. The letter talks about the tool plate used to make lenses, consisting of disc of glass, of the same size or a bit larger than the lens to be ground. The letter also says that the tool plate was preliminarily deepened by means of a smaller disc of glass with sharp emery, abrading more about the center than the edge. The random movements imparted by the artisan were such that the two surfaces being abraded, the lens and the tool plate, formed a pair of spherical surfaces, one concave and the other convex. Torricelli discloses a secret of lens-making that included polishing the lens on a thin plate of lead or tin laid on the same tool plate that served for grinding. Source


Magrin D.,National institute for astrophysics | Munari M.,National institute for astrophysics | Pagano I.,National institute for astrophysics | Piazza D.,University of Bern | And 14 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The project PLAnetary Transits and Oscillations of stars (PLATO) is one of the three medium class (M class) missions selected in 2010 for definition study in the framework of the ESA Cosmic Vision 2015-2025 program. The main scientific goals of PLATO are the i) discovery and study of extra-solar planetary systems, (including those hosting Earth-like planets in their habitable zone) by means of planetary transits detection from space and radial velocity follow-up from ground, and ii) the characterization of the hosting stars through seismic analysis, in order to determine with high accuracy planetary masses and ages. According to the study made by the PLATO Payload Consortium (PPLC) during the PLATO assessment phase, the scientific payload consists of 34 all refractive telescopes having small aperture (120 mm) and wide field of view (greater than 1000 degree2) observing over 0.5-1 micron wavelength band. The telescopes are mounted on a common optical bench and are divided in four families with an overlapping line-of-sight in order to maximize the science return. In this paper, we will describe the detailed design of the Telescope Optical Units (TOUs) focusing on the selected optical configuration and the expected performances. © 2010 SPIE. Source


Homan C.D.,Goethe University Frankfurt | Homan C.D.,University of Wuppertal | Volk C.M.,Goethe University Frankfurt | Volk C.M.,University of Wuppertal | And 6 more authors.
Atmospheric Chemistry and Physics | Year: 2010

We present airborne in situ measurements made during the AMMA (African Monsoon Multidisciplinary Analysis)/SCOUT-O3 campaign between 31 July and 17 August 2006 on board the M55 Geophysica aircraft, based in Ouagadougou, Burkina Faso. CO 2 and N 2O were measured with the High Altitude Gas Analyzer (HAGAR), CO was measured with the Cryogenically Operated Laser Diode (COLD) instrument, and O 3 with the Fast Ozone Analyzer (FOZAN). We analyse the data obtained during five local flights to study the dominant transport processes controlling the tropical tropopause layer (TTL, here ∼350-375 K) and lower stratosphere above West-Africa: deep convection up to the level of main convective outflow, overshooting of deep convection, and horizontal inmixing across the subtropical tropopause. Besides, we examine the morphology of the stratospheric subtropical barrier. Except for the flight of 13 August, distinct minima in CO 2 mixing ratios indicate convective outflow of boundary layer air in the TTL. The CO 2 profiles show that the level of main convective outflow was mostly located at potential temperatures between 350 and 360 K, and for 11 August reached up to 370 K. While the CO 2 minima indicate quite significant convective influence, the O3 profiles suggest that the observed convective signatures were mostly not fresh, but of older origin (several days or more). When compared with the mean O3profile measured during a previous campaign over Darwin in November 2005, the O 3 minimum at the main convective outflow level was less pronounced over Ouagadougou. Furthermore O 3 mixing ratios were much higher throughout the whole TTL and, unlike over Darwin, rarely showed low values observed in the regional boundary layer. Signatures of irreversible mixing following overshooting of convective air were scarce in the tracer data. Some small signatures indicative of this process were found in CO 2 profiles between 390 and 410K during the flights of 4 and 8 August, and in CO data at 410K on 7 August. However, the absence of expected corresponding signatures in other tracer data makes this evidence inconclusive, and overall there is little indication from the observations that overshooting convection has a profound impact on gas-phase tracer TTL composition during AMMA. We find the amount of photochemically aged air isentropically mixed into the TTL across the subtropical tropopause to be not significant. Using the N 2O observations we estimate the fraction of aged extratropical stratospheric air in the TTL to be 0.0±0.1 up to 370K during the local flights. Above the TTL this fraction increases to 0.3±0.1 at 390K. The subtropical barrier, as indicated by the slope of the correlation between N 2O and O 3 between 415 and 490 K, does not appear as a sharp border between the tropics and extratropics, but rather as a gradual transition region between 10° N and 25° N where isentropic mixing between these two regions may occur. © 2010.Author(s). Source


Di Caprio G.,CNR Institute for Microelectronics and Microsystems | Gioffre M.A.,CNR Institute for Microelectronics and Microsystems | Saffioti N.,CNR Institute for Microelectronics and Microsystems | Grilli S.,Istituto Nazionale di Ottica Applicata | And 5 more authors.
IEEE Journal on Selected Topics in Quantum Electronics | Year: 2010

A digital holographic microscope (DHM) has been employed in the retrieval and analysis of morphological images of bovines sperm cells. Digital holography is a noncontact technique capable of investigating the shape of the sample without altering its characteristics and has been used for the first time in retrieving quantitative morphological information of sperm cells. Different spermatozoa have been analyzed by means of this technique allowing us to obtain 3-D images with precise topographical details and valuable information about morphological defects, provided with biological considerations. Moreover, by making use of a microfluidic system, the digital holographic technique has been employed to analyze unstained spermatozoa in their natural physiological surroundings. Detailed information on morphological images of spermatozoa acquired by DHM is expected to provide a better understanding of various reproductive pathways, which, in turn, can help in improving infertility management. This could constitute the basis of an alternative method for the zoothecnic industry aimed at the investigation of morphological features and the sorting of the motile sperm cells. © 2010 IEEE. Source

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