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The food safety issue is among the cornerstones of the environmental protection schemes worldwide and beside hazard issues, there is great concern about monitoring of food spoilage in a reliable way. Current practices of assessment of food spoilage still relies heavily on regulatory inspection and sampling regimes. A portable photonic multisensor device for the detection of food contaminations, spoilage and fraud is the objective of the EU PhasmaFOOD project. It will integrate different capabilities: spectroscopic detection (VIS/ NIR), imaging, smart signal processing, data analysis and comparison with updated models on cloud platform hosting data set for training and calibration of food analysis algorithms, user friendly interfaces by smartphone/tablet/PC also through wireless connection.

In this work we propose a wet sample handling technique which enables the simultaneous collection of X-ray fluorescence (XRF) spectra and X-ray phase contrast imaging (XPCI) using a few microliters drop confined on a superhydrophobic surface. To this purpose, we fabricated and tested a superhydrophobic patterned surface entailing an hydrophilic region which leads to pinning of the drop, enabling X-ray beam effortless alignment and measuring in liquid phase. Our technique allows to acquire capillary-free XRF spectra, resulting in a significant fluorescence detection gain, which is particularly interesting for light elements. Simultaneous XPCI provides sample geometry assuring a fine control of the experimental conditions and allowing real time monitoring of the drop during measurements. As an additional advantage - after solvent evaporation - the solute is deposited on a precise spot, greatly increasing its concentration allowing further measurements, such as X-ray microanalysis and X-ray diffraction. These results could have potential applications in the study of blood proteins, such as ferritin and low density lipoprotein, which are usually available in very limited quantity.

Two-dimensional photonic crystals have been fabricated by x-ray lithography and reactive ion etching on an air/GaAs/AlGaAs asymmetric waveguide. The shape of the lattice unit cell has been varied by exploiting x-ray diffraction effects and nonlinear response of resists during the development process. Rings with or without a central pillar have been fabricated with a resolution down to 50 nm. Lithographic details are described to show the accuracy of this fabrication technique. Optical characterization has been performed showing the presence of a well defined photonic band structure as well as band anti-crossing. The results are discussed and compared with theoretical calculations of the photonic band dispersion. Structures with high dielectric fraction are shown to yield photonic modes with small line widths and low propagation losses. The reliability and the precise control of the fabricated sample structures make this lithographic method useful for a full investigation of optical properties on the dependence of the lattice unit cell shape.

Infrared Microspectroscopy (IRMS) has been proposed as a powerful diagnostic tool in biology, due to the rich molecular, structural and conformational information contained in IR spectra of cells and tissues. In particular, IRMS of live cells in microfluidic devices has to cope with the strong water absorption in the medium infrared spectral region and the scarce knowledge about fabrication protocols suitable for microstructuring infrared-transparent materials. Based on these motivations we are developing and testing a class of microfluidic devices consisting of a patterned photoresist sandwiched between two CaF2 optical windows.In this paper we propose solutions to a few specific issues, namely, (i) the poor resist adhesion during micro-fabrication processes due to the low surface energy of CaF2, (ii) the potentially harmful effects of CaF2 dissolution on interesting cellular lines (such as neurons or stem cells), (iii) the sealing of the devices.Specifically, we modified the surface properties of CaF2 substrates by sputtering a thin layer of Si, as to obtain the following advantages: (a) all lithographic steps can be performed as if they were carried out on silicon wafers; (b) the chemical functionalization and nanostructuring of the surface in contact with cells can be obtained by usual protocols used for Si; (c) the deposited silicon separates living cells and their environment from CaF2. A device sealing process is discussed, based on a polymer bonding protocol, in order to tune the content of residual solvent. Finally, we present IR hyperspectral images acquired on MCF-7 living cells, cultured inside our devices for 48 h.

We report on the growth of microns long Mn-catalyzed GaAs nanowires. alpha-Mn is found on top of the wires, demonstrating that Mn acts as the growth catalyst. Transport measurements show that the wires have a p-behavior. Luminescence shows a peak at 1.522 eV. The blue shift with respect to bulk GaAs is not due to quantum effects.

Photonic crystals (3D) represent one of the most important building blocks towards the achievement of a full optics communication technology. So far the largest interest has been attracted by two-dimensional photonic crystals because they are potentially more amenable to fabrication and much closer to application. Straightforward application of the photonic band gap concept is generally thought to require three-dimensional (3D) photonic crystals that, however, represent a challenge from a fabrication point of view. Recent works have shown that 3D metallic PC can be fabricated and that they can be advantageous in the low frequency region where the metals become almost completely reflectors. In this work we show the possibility to fabricate 3D PC structures by X-ray lithography. Gold and nickel 3D photonic crystals with threefold (Yablonovite) and fourfold rotation symmetry have been fabricated with a lattice parameter ranging from 1 ?m down to 300 nm. The total thickness of the 3D PC is of the order of 10 ?m, a value which should allow to achieve a complete bulk behavior. This is supported by variable angle reflectance measurements, which have shown clear indications for true 3D dimensionality of our samples.

We present the fabrication of high refractive index contrast two-dimensional photonic crystal (2D-PC) slab waveguides. 2D photonic crystal structures, consisting of a periodic array of holes in a GaAs matrix, are obtained by nanopatterning of epitaxially grown GaAs/AlGaAs heterostructures. Two different PC structures will be described in detail: (i) an asymmetric 2D-PC slab waveguide obtained by selective oxidation which transforms the Al-rich AlGaAs cladding layer underneath the PCs into aluminium oxide and (ii) a symmetric 2D-PC slab waveguide obtained by removing the oxide (free standing structure).

Different laser induced diagnostics, originally developed for different purposes including material characterization and environmental monitoring, have been applied in the field of Cultural Inheritance preservation with the aim to facilitate successive conservation and restoration actions. In this paper results relevant to three different techniques are reviewed. The use of topologic laser and 3D sensor in checking small artifacts and large surfaces is discussed, the application of Speckle interferometry to defect analysis of ceramic artwork is represented, a demonstration of the capabilities of a time resolved LIF system in the characterization of surface composition of ancient ceramics and frescoes is finally given.

A coherent laser sensor, able to achieve measurement of absolute and relative distance of real targets, has been developed for advanced robotic applications. A brief theoretical description of the expected behavior of such system is reported for static and dynamic targets; the theoretical range error dependence from the signal to noise ratio is also described. Experimental results for measurements of static and vibrating real targets are discussed.

There is now an increasing need for research to meet the objectives of vehicle energy conservation and the case for this is presented here. It illustrates the need for basic research in areas such as heat transfer and combustion in alternative engines, instrumentation control, rheology and manufacturing processes for vehicle components and materials. Car manufacture needs research on thermomechanical treatments application of optimization theory, acoustic diagnostics and assembly of mechanical parts by robots. The best way of attracting the attention of the university community to such research are also discussed, emphasizing the role of establishing good communication channels.

In some recent papers (1-3) methods have been given for calculating the potential energy of strongly deformed nuclei under the usual assumptions of the liquid drop model. These methods have been applied to the calculation of the symmetric saddle shape (2), giving results in good accordance with the ENIAC computat ions of FRASKEL and METROi'OL~S (% Also these computations show (~-3) tha t sufficiently elongated shapes might be unstable with respect to asymmetric deformations. We will here apply the formulae already derived in (~,z) to the problem of the existence and character of asymmetric equilibrium shapes. Considering deformations of P2 and Pa type, only, superimposed on the basic ellipsoid, one may write for the potential energy, in a compact form

Patterned arrays of magnetic wires, dots and anti-dots have attracted a lot of interest both for their potential applications in magnetic data-storage devices and for the investigation of magnetic phenomena in low-dimensional systems. However the employment of micro- and nano-structures in magnetic high density recording media and non-volatile RAM is not trivial: compared to the case of a continuous film, the small size of the islands increases the effects of the demagnetizing field, affecting the static and dynamic magnetic properties. Moreover, some new effects arise due to the lateral confinement of the structures, e.g.: quantized spin-wave modes. These latter effects are of great interest also from a fundamental point of view.

In this paper we report results obtained in the fabrication and use of novel coded diffractive nano-optics that, beyond focusing, can perform new optical functions. In particular, the intensity of light in the space beyond the optical elements can be redistributed with almost complete freedom. These novel X-ray optical elements have been tested and found to perform multi-focusing in single or multiple focal planes and beam shaping of a generic monochromatic beam into a desired continuous geometrical pattern. Already available extreme ultraviolet and X-ray sources are suitable as ideal sources for such diffractive optical elements. Their new optical functions have been tested in differential interference contrast microscopy and we suggest their use also in maskless lithography and chemical vapour deposition induced by extreme ultraviolet and X-ray radiation.

Second-harmonic (SH) reflection and diffraction measurements are performed, at the wavelengths of a Ti:sapphire laser on a GaAs/AlGaAs photonic crystal waveguide patterned with a square lattice, the basis consisting of rings of air in the dielectric matrix. The measured angles of diffracted SH beams agree with those predicted from nonlinear diffraction conditions. Results for reflected and diffracted SH intensities as a function of incidence angle, polarization, and pump wavelength show that, due to the low air fraction of the photonic crystal, the reflected one is dominated by the crystalline symmetry of GaAs, while the diffracted one is related to the photonic crystal structure. The large diffraction-to-reflection ratio points to the importance of nonlinear diffraction in photonic crystals. Preliminary measurements in the 1500nm range reveal explicit features related to photonic modes.

Here we present the optimization of fabrication steps for realizing an infrared-visible microfluidic chip to study single-living cell behaviour in physiological environment by synchrotron radiation FTIR microspectroscopy. We optimized subtractive and additive lithographic processes on CaF"2 substrate, employing X-ARP 3100/10 photoresist both as etching-mask and for the device fabrication. Using prototype microfabricated liquid cells 9 and [email protected] thick, we measured the response of small groups of THP1 monocytic cells to mechanical compression and chemical stimulation with fMLP using conventional IR globar source, aiming to evaluate biochemical rearrangements of leukocytes during the capillary circulation or recruitment processes. Stimulated monocytes have spectral features recognizable, differentiating them from un-stimulated, especially affecting the spectral region 1280-1000cm^-^1, characteristic of nucleic acids and carbohydrates, and specific band ratios, such as proteins on lipids and methylene on methyl. Spectra variations have been correlated with biochemical events such as transcription, synthesis of new-proteins and variations in membrane fluidity.

First experiments demonstrating the suitability of novel microfabricated fluidic devices for measuring living cells in physiological environment by synchrotron radiation (SR) Fourier Transform Infrared microspectroscopy (μ-FTIR) are presented. The devices were fabricated on CaF 2 windows, using the photoresist XARP 3100/10 to define the liquid cell lay-out. Therefore, the sample holder is transparent to both visible and infrared light, robust, completely recyclable and with a precise spacing. Using prototype devices of thicknesses 9, 5 and 3 μm, we studied the response of the U937 monocytic cell line to mechanical compression. The temporal evolution of the FTIR spectra, characteristic for the status of living cells, was used to monitor the cellular system stability in time. Protein biosynthesis and lipid metabolism alterations upon deformation have been identified by monitoring specific cell band ratios such as amide I to amide II, amide I to lipids, methylene to methyl and asymmetric to symmetric stretching of phosphates. Taking advantage of the high brilliance of the synchrotron radiation, chemical maps of monocyte cells were collected, demonstrating the versatility of the device.

GaAs nanowires have been grown on SiO2 and GaAs by molecular beam epitaxy using manganese as growth catalyst. Transmission electron microscopy shows that the wires have a wurtzite-type lattice and that alpha-Mn particles are found at the free end of the wires. X-ray absorption fine structure measurements reveal the presence of a significant fraction of Mn-As bonds, suggesting Mn diffusion and incorporation during wire growth. Transport measurements indicate that the wires are p-type, as expected from doping of GaAs with Mn.

The aim of this paper is to demonstrate that efficient fiber-waveguide optical coupling can be achieved using a multilevel phase diffractive element (PDE) fabricated directly on the top of the fiber by means of e-beam lithography. The diffractive phase element is calculated to focus and reshape the gaussian symmetric beam exiting a single-mode fiber into a desired asymmetric intensity distribution at the waveguide input plane. Phase modulation is obtained by multilevel profiling a polymeric material coated on the top of the fiber by means of a specific fabrication process including e-beam lithography and chemical etching. Experimental results obtained for fiber-waveguide coupling with a 20-µm diameter diffractive element are also presented.

Photonic crystals (3D) represent one of the most important building blocks towards the achievement of a full optics communication technology. So far the largest interest has been attracted by two-dimensional photonic crystals because they are potentially more amenable to fabrication and much closer to application. Straightforward application of the photonic band gap concept is generally thought to require three-dimensional (3D) photonic crystals that, however, represent a challenge from a fabrication point of view. Recent works have shown that 3D metallic PC can be fabricated and that they can be advantageous in the low frequency region where the metals become almost completely reflectors. In this work we show the possibility to fabricate 3D PC structures by X-ray lithography. Gold and nickel 3D photonic crystals with threefold (Yablonovite) and fourfold rotation symmetry have been fabricated with a lattice parameter ranging from 1 μm down to 300 nm. The total thickness of the 3D PC is of the order of 10 μm, a value which should allow to achieve a complete bulk behavior. This is supported by variable angle reflectance measurements, which have shown clear indications for true 3D dimensionality of our samples.

We present the fabrication of high refractive index contrast two-dimensional photonic crystal (2D-PC) slab waveguides. 2D photonic crystal structures, consisting of a periodic array of holes in a GaAs matrix, are obtained by nanopatterning of epitaxially grown GaAs/AlGaAs heterostructures. Two different PC structures will be described in detail: (i) an asymmetric 2D-PC slab waveguide obtained by selective oxidation which transforms the Al-rich AlGaAs cladding layer underneath the PCs into aluminium oxide and (ii) a symmetric 2D-PC slab waveguide obtained by removing the oxide (free standing structure).

The present research work is devoted to the realization of an efficient optical coupling between single-mode fiber and rectangular waveguide. The outcoming laser beam exiting from the fiber has a gaussian transversal field distribution. On the contrary, the single-mode waveguide has an asymmetric transversal field distribution in X and Y-axis. The problem of transforming the outcoming circular laser beam onto a rectangular, size adjusted, spot can be solved realizing directly on the top of the fiber a diffractive optical element. This optic element is able to redistribute the diffractive electromagnetic field on a selected area by a suitable phase modulation of the light, in analogy with what happens for Fresnel zone plate lenses. Phase modulation is obtained by a multilevel profiling of a polymeric material coating the top of the fiber by means of e-beam lithography. The design of diffractive optical elements has been realized using our own algorithm and code. Focalization experiments have been made with the use of a 1550nm wavelength laser. Description of the lithography and fabrication processes are shown as well.

Two-dimensional photonic band gap structures were fabricated by x-ray lithography combined with, ion etching on metalorganic chemical vapor deposition grown GaAs/AlGaAs waveguides. Such structures, more amenable to fabrication than fully three-dimensional photonic crystals, allow the confinement of light in the third direction using index guiding. The feasibility of complex high-resolution (down to 50 nm) unit cell fabrication has been demonstrated by exploiting x-ray diffraction and nonlinear resist response during the development process. Optical characterizations of some samples were performed. These characterizations show the presence of well-defined photonic band gap structures and second harmonic property generation. The results have been discussed and compared with theoretical simulation

Nonlinear reflection and diffraction measurements have been performed on a GaAs/AlGaAs photonic-crystal waveguide patterned with a square lattice: The basis in the two-dimensional unit cell consists of rings of air in the dielectric matrix. The measured angles of diffracted second-harmonic beams agree with those predicted for nonlinear diffraction conditions, Results for second-harmonic intensities as a function of incidence angle, polarization, and pump wavelength show that the reflected second-harmonic signal is dominated by the crystalline symmetry of GaAs, whereas nonlinear diffraction is determined by the photonic-crystal structure.

Second-harmonic generation (SHG) measurements in reflection on a ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_{0.25}{\mathrm{Ga}}_{0.75}\mathrm{As}$ photonic crystal waveguide show a resonant enhancement when the pump beam is frequency and momentum matched with the photonic modes in the slab. The enhanced SH signal is observed in the form of resonant peaks, unlike in linear reflectance spectra. The observations are in very good agreement with a full 3D calculation of the anisotropic mode dispersion in the photonic crystal slab. The present results open the way towards realizing the extraordinary enhancement of SHG which was recently predicted [A. R. Cowan and J. F. Young, Phys. Rev. B $65,$ 085106 (2002)], and also demonstrate the potential of SHG as a nonlinear spectroscopic tool for optical studies of photonic crystals.