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This work discusses the phenomenon of multipath interference in bend-insensitive optical fibers and components that arises when these devices work at wavelengths approaching the multimode regime. After recalling the rationale behind this study and some technical hints about the measurement setup, the paper focuses on the characterization of field-installable connectors and optical fiber splitters...
Keratoconus is an ophthalmic disease in which the cornea acquires an abnormal conical shape that prevents the correct focusing on the retina, causing visual impairment. The late diagnosis of keratoconus is among the principal causes of corneal transplantation surgery. In several previous studies, a different organization sutural lamellae was observed in keratoconic corneas compared to healthy corneas...
The current diagnostic standard for detection of bladder tumors is standard white light cystoscopy. The major concerns related to cystoscopy include its invasive, causes discomfort to the patient and also misses flat tumors such as carcinoma in situ (CIS). Grading and staging of tumors would help the clinician for selecting the proper treatment thereby preventing recurrence and progression of bladder...
We investigated the capacity of tumour cells to populate the gaps of three-dimensional microstructures (3D-SMS) formed by periodic arrays of parallel 3-μ m-thick silicon walls separated by 5-μ m-wide, 50 μ m-deep air gaps. To evaluate a possible correlation between this feature and cell aggressiveness, we tested eight human tumour cell lines with a well known different aggressive potential. The qualitative...
The thermal response of an active optical fiber cable, put in contact with a sample of Neapolitan yellow tuff with varying moisture content, has been measured by a Brillouin Optical Time-Domain Analysis (BOTDA) sensor. Preliminary results demonstrate that the thermal response acquired by the BOTDA sensor can be used to monitor the moisture content in the tuff material.
A new source of high-power broadband THz radiation has been built in Naples, Italy. The source is based on two-colours mixing of ultrashort femtosecond light pulses. The source can deliver THz frequencies in the range 0.1–30 THz, with pulses of sub-picosecond time duration and having a peak electric field amplitude as high as 1 MV/cm. A characterization of the source is given in this work together...
Optical sensors have been extensively studied in order to develop new methods of investigation for different materials. In particular, light scattering and absorption in biological tissues have been investigated for diagnostic and therapeutic applications. Here we present an experimental work devoted to develop a new kind of optical sensor based on the random laser emission. Such an optical phenomenon...
One of the most exciting challenges of neurosciences in the last few years is the real-time recording of neuronal activity with single cell resolution across the entire brain. Thanks to the use of optical methods, together with animal models in which the whole encephalon is optically accessible, this goal is getting within reach. In this work, we use a transgenic zebrafish line expressing the genetically...
Plant roots of Arabidopsis thaliana can be imaged at high spatial resolution on a large field of view by light sheet fluorescence microscopy, such as Selective Plane Illumination Microscopy (SPIM). Root growth can be observed in 3D over various time scales, in controlled, quasi-physiological conditions. We show that SPIM combined with Forster Resonance Energy Transfer is well suited to observe calcium...
An on-chip opto fluidic sensor based on liquid jet waveguide has been developed. Laser induced fluorescence takes advantage of the waveguiding nature of a jet stream to detect, at very low detection limits, common fluorophore. Tests performed on eosin Y in water demonstrated detection at 38 pM level. The proposed approach provides high excitation and collection efficiency of the sample under analysis,...
Zebrafish is a model organism in developmental biology for several reasons, including the fact that Zebrafish embryos are translucent and this enables the study of tissue development under a microscope. This study is aimed at developing methodologies for characterizing the metabolic state of different tissues during development and in different controlled environmental conditions. Two-photon excited...
Recent discoveries about the optical properties of red blood cells (RBCs) and the perspective of using them as liquid micro-lenses can now be used to explain, and may eventually be used to predict, erythrocyte shape and to screen for blood disease. Nowadays, blood smear test represents a simple and cheap method to estimate the morphology of blood components and to achieve qualitative information regarding...
A reconfigurable Photonic Integrated Circuit for mode multiplexing and demultiplexing in a few-mode fiber is proposed and demonstrated. The circuit allows to selectively excite and demultiplex modes LP 10 and LP 11a with an estimated efficiency in the order of −6 dB and mode-dependent losses smaller than 1 dB. Mode cross-talk is measured as low as −20 dB. Two-mode SDM fiber transmission and channel...
We report on colloidal PbS quantum dot near infrared photoconductors operating at low voltage. In order to maximize the device sensitivity, we exploited the advantages of different measurement techniques and methods for dark current cancellation and noise reduction including the DC volt-amperometric measurement with offset cancellation, a Wheatstone-bridge configuration and impedance measurements...
Here, crater geometries produced by the ablation process during laser induced plasma spectroscopy elemental depth profiling, are investigated by means of 3D microscopy. Deep depth profiles are often required in the characterization of cultural heritage artefacts such as archaeological bronzes. This work aims at finding the optimal irradiance conditions in order to sample large depths in bronzes with...
CH3NH3PbI3 layers have been prepared by two-step procedure (spin coating and dipping) on flat substrates under ambient conditions with uncontrolled relative humidity. The films have been characterized by means of scanning electron microscopy, absorption coefficient and x-ray diffraction when varying spinning rate, washing procedure, and dipping time. In particular a novel washing procedure has been...
In this paper, a methodology for the analysis of subcellular morphology with chemical specificity, for images obtained by Stimulated Raman Scattering microscopy, is described. In order to detect microstructures inside the cells, a segmentation method based on a threshold algorithm and on a region growing process is proposed. Validation tests on images of polystyrene beads and of on adipocyte cells...
Conductive non stoichiometric TiO2-based films attract considerable interest for their photocatalytic, photovoltaic and photoelectrochemical applications. In this work, transparent and conductive TiOx and TiO2:Nb films were fabricated by e-beam evaporation at 250°C in oxygen deficient atmosphere starting from commercial powders, while TiO2:Nb films and TiO2:Nb/Ti multilayer systems were grown at room...
Traditionally, the LIDAR technique has been successfully applied to the detection of concentrated smoke plumes emitted by wildfires. In this paper, it is shown how LIDAR measurements can also be deployed to determine the profile of the backscattering coefficient in the presence of widespread smoke, which can be the consequence of strong wind dispersion or non-concentrated sources. To this end, innovative...
Gold nanorods (GNRs) were investigated to enhance light absorptionin co-sentitized dye solar cells (c-DSSC), thanks to their plasmonic characteristics. Pastes were obtained by directly mixing GNRs with titania. The resulting thin films differ for sintering conditions and GNRs concentration. The reported study is based on the absorbance spectra of the different samples, together with SEM and TEM to...
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