Alessio Crescitelli

• PhD
• Researcher at Italian National Research Council

In this work, we present a low-noise tunable DC-DC converter designed for driving high-resistance thin film heaters (in the order of a few of k). The converter features a two-stage design comprising a voltage-boosting initial stage and a subsequent voltage-regulating stage where carefully selected LC and RC filters are employed to achieve low outpu...

A pixeled plasmonic metasurface (MS) has been developed as a surface-enhanced infrared absorption (SEIRA) spectroscopy substrate to monitor the denaturation process of a protein A (PA) monolayer. The different pixels of the MS have been properly engineered to monitor different regions of the electromagnetic spectrum. Specifically, these pixels have...

This work presents a portable system developed to perform biochemical analyses requiring both temperature sensing for the thermal sample treatment and optical sensing to detect the analyte. To achieve this goal, we coupled a system-on-glass, hosting on a single glass substrate a thin film transparent heater and two temperature sensors, with interfa...

We apply surface-enhanced infrared absorption (SEIRA) spectroscopy to monitor the denaturation process of a surface-bound protein A monolayer. Our proposed platform relies on a plasmonic metasurface comprising different spatial subregions (“pixels”) that are engineered to exhibit different resonances covering the infrared region of the electromagne...

The need for miniaturized biological sensors which can be easily integrated into medical needles and catheters for in vivo liquid biopsies with ever-increasing performances has stimulated the interest of researchers in lab-on-fiber (LOF) technology. LOF devices arise from the integration of functional materials at the nanoscale on the tip of optica...

In this paper we present a device integrating on a single glass substrate a transparent heater and two resistive temperature sensors. Both heater and sensors are constituted by ITO/Au/ITO stacked film, whose thicknesses have been optimized in order to achieve at the same time good electrical conductivity (about 10 <sup xmlns:mml="http://www.w3.org/...

We propose and demonstrate a sensing platform based on plasmonic metasurfaces for the detection of very low concentrations of deoxyribo-nucleic acid (DNA) fragments. The platform relies on surface-enhanced infrared absorption spectroscopy, implemented via a multispectral metasurface. Specifically, different regions (“pixels”) are engineered so as t...

The ability to control light at the nanoscale is at the basis of contemporary photonics and plasmonics. In particular, properly engineered periodic nanostructures not only allow the inhibition of propagation of light at specific spectral ranges or its confinement in nanocavities or waveguides, but make also possible field enhancement effects in vib...

The steadily increasing demand for accurate analysis of vitamin D level, via measurement of its best general marker, 25-hydroxyvitamin D (25(OH)D), pushes for the development of novel automated assays capable of working at very low concentrations. Here, we propose a plasmonic biosensor of 25(OH)D3 (calcifediol) based on surface-enhanced infrared ab...

The valorization of sugar beet pulp (SBP) from sugar industry as a source of valuable substances has been taken in consideration in this work. In particular, the eco-friendly extraction of pectins with citric acid has been adopted as a preliminary step in a simplified biorefinery concept where the pectin-free solid is subsequently subjected to a to...

The reduction of alcohol content in wines has two main objectives, the former is decreasing the wines’ strength and the latter is producing new low alcohol beverages. To accomplish the latter, in this study, we focused on the dealcoholization of a white wine (cv Falanghina, 12.5 vol%) obtained from an ancient Italian grape variety that has recently...

Today, nanophotonics still lacks components for modulation that can be easily implementable in existing silicon-on-insulator (SOI) technology. Chalcogenide phase change materials (PCMs) are promising candidates for tuning in the near infrared: at the nanoscale, thin layers can provide enough contrast to control the optical response of a nanostructu...

‘Annurca’ apple, a southern Italian cultivar, is known for its reddening, taste and flavour among the other types of apples, and also for health promoting effects. The aim of this study is to evaluate the effect of a novel pre-treatment, by dipping in a solution containing trehalose, sodium chloride, sucrose, and of drying process conditions (tempe...

Infrared spectroscopy is an effective technique extensively used in research and industry for the label-free and unambiguous identification of molecular species. However, the sensitivity of this technique is severely limited as a result of Beer’s law and, the small infrared absorption cross-section that make prohibitively weak the absorption signal...

InfraRed (IR) spectroscopy is a well-known tool, widely used as label free technique for the unequivocal identification of molecular species. Unfortunately, this technique shows a very low molecular absorption cross-section of infrared vibrations and so a large amount of material is necessary for precise determinations. Consequently, the spectrosco...

Abstract In this work, we report on the first demonstration of Lab on Fiber (LOF) dosimeter for ionizing radiation monitoring at ultra-high doses. The new dosimeter consists in a metallo-dielectric resonator at sub-wavelength scale supporting localized surface plasmon resonances realized on the optical fiber (OF) tip. The resonating structure invol...

The influence of an alternative chemical pretreatment on dehydration and rehydration of an Italian ecotype pumpkin was investigated. The pretreatment consisted of soaking the slices in a diluted solution of trehalose, sucrose and NaCl. Hot air-drying was performed in a convective dryer at temperatures of 55, 60, 65 and 70°C. Samples treated prior t...

Improving the sensing capabilities of miniaturized probes nanofabricated on the tip of optical fibers is crucial for a large number of sensing applications in remote and harsh environ-ments. While most research efforts are directed towards developing improved fabrications techniques or more sensitive structures, we show that the performance of thes...

Due to their increasing use in agriculture, the presence of pesticide residues in food and water currently represents one of the major issues for the food safety. Among the pesticides, organophosphate and carbamate species are the most used, and their toxicity is mainly due to their inhibitory effect on acetylcholinesterase (AChE). For this reason,...

A preliminary characterization of two new soft-seeded pomegranate varieties (MR-100® and KINGDOM®) based on their main physico-chemical and nutritional parameters was reported. The two varieties showed significant differences (p ≤ 0.05) in polyphenols, anthocyanins and antioxidant activity. Kingdom pomegranate had higher polyphenols (2524.73 mg GAE...

Fatty acid and sterol content of oil from nuts (cv Tonda di Giffoni) affected by two different biotic damages were characterized. Hazelnuts were sorted by a visual inspection of the kernels in three different samples (cimiciate, apparently healthy and moldy). The oil was extracted and analyzed by gas–liquid chromatography coupled to a flame ionizat...

We present an experimental investigation of nanoSQUIDs based on niobium nitride films. Niobium nitride has a relatively high critical temperature and a large upper critical magnetic field, making it a good material for superconducting electronics working in high magnetic field. We have fabricated nanoSQUIDs using electron beam lithography lift-off...

Five onion landraces belonging to Bianca di Pompei cv., cultivated in Campania region (Italy), were characterized for their main quality parameters. The onion landraces were harvested at the end of the growth cycle corresponding to the ripening time and harvest month, respectively: February, March, April, May, and June. The total content of volatil...

A combined pretreatment of trehalose (0.5 %) and NaCl (0.5 %) solution was applied prior to drying eggplant to reduce shrinkage, browning and loss of polyphenols. Drying behaviour of eggplant slabs was experimentally examined in a convective dryer at temperatures of 50, 60 and 70 °C and at 2.3 m/s air velocity. Then the effects of pretreatment and...

Highly tunable dielectric metasurfaces based on subwavelength thick silicon nano-posts encapsulated in a thin elastic polymer are demonstrated. The proposed platform simultaneously provides a high tuning range, high efficiency, polarization independence, and diffraction limited performance. This platform is highly versatile for developing ultra-sli...

This review presents an overview of “Lab on Fiber” technologies and devices with special focus on the design and development of advanced fiber optic nanoprobes for biological applications. Depending on the specific location where functional materials at micro and nanoscale are integrated, “Lab on Fiber Technology” is classified into three main para...

We report on the first demonstration of a proof-of-principle optical fiber ‘meta-tip’, which integrates a phase-gradient plasmonic metasurface on the fiber tip. For illustration and validation purposes, we present numerical and experimental results pertaining to various prototypes implementing generalized forms of the Snell’s transmission/reflectio...

An impedimetric label-free immunosensor on disposable screen-printed carbon electrodes (SPCE) for quantitative determination of Ochratoxin A (OTA) has been developed. After modification of the SPCE surface with gold nanoparticles (AuNPs), the anti-OTA was immobilized on the working electrode through a cysteamine layer. After each coating step, the...

We realize the first optical-fiber “meta-tip” that integrates a metasurface on the tip of an optical fiber. In our proposed configuration a Babinet-inverted plasmonic metasurface is fabricated by patterning (via focused-ion-beam) an array of rectangular aperture nanoantennas in a thin gold film. Via spatial modulation of the nanoantennas size, we p...

We report on the first example of a “meta-tip” configuration that integrates a metasurface on the tip of an optical fiber. Our proposed design is based on an inverted-Babinet plasmonic metasurface obtained by patterning (via focused ion beam) a thin gold film deposited on the tip of an optical fiber, so as to realize an array of rectangular apertur...

We present an experimental investigation aimed to fabricate a nanoSQUID for high-magnetic-field applications. In particular, we produced niobium films having different thicknesses (5, 10, and 15 nm) with passivation layers to investigate the trans- port properties of very thin niobium film in high magnetic field parallel to the film plane. The resu...

We realize the first optical-fiber “meta-tips” implementing in the near-infrared the beam-steering with increasing angles, up to the limit case of surface-waves excitation. We also explore their capability to work as local refractive index sensor.

The integration of microfluidics and photonic biosensors has allowed achievement of several laboratory functions in a single chip, leading to the development of photonic lab-on-a-chip technology. Although a lot of progress has been made to implement such sensors in small and easy-to-use systems, many applications such as point-of-care diagnostics a...

This work deals with a novel Lab-on-Fiber biosensor able to detect in real time thyroid carcinomas biomarkers. The device is based on a gold nanostructure supporting localized surface plasmon resonances (LSPR) directly fabricated on the fiber tip by means of electron beam lithography and lift-off process. Following a suitable chemical and biologica...

Botrytis cinerea is the causative agent of gray mold disease, which causes considerable economic losses to winemakers. The extent of gray mold infection of winegrapes is commonly visually estimated, a method that is prone to assessor bias. Here, we used rapid and simple enzyme-based screening consisting of carbon-electrode, screen-printed amperomet...

A lactate oxidase amperometric biosensor was developed and optimized for the malolactic fermentation monitoring during winemaking process. Lactate oxidase enzyme was immobilized on prussian blue modified screen-printed carbon electrode in order to reduce the electrochemical interferences due to the high content of electroactive compounds abundant i...

Drying is an important process for the conservation and subsequent marketing of fruits due to their high water activity which makes them highly perishable. Dried products have to meet high quality standards, and one of the most important aspects in fruit drying is the need to obtain products with uniform organoleptic properties. Therefore, the know...

Lutein, a yellow xanthophyll, is a very important nutritional compound in human diet because of its positive effects in the prevention of age-related macular degeneration and other eye diseases. In this study a rapid and food-grade solvent extraction for lutein content was performed on tomato peel, provided by a local tomato processing factory, wit...

The drying of grapes is a more complex process compared to the dehydration of other agricultural materials due to the necessity of a pretreatment operation prior to drying. Grape drying to produce raisins is a very slow process, due to the peculiar structure of grape peel, that is covered by a waxy layer. Its removal has been so far carried out by...

The ‘‘Lab-on-Fiber ’’ technology essentially envisages a novel class of advanced, multifunctional photonic devices and components arising from the integration onto optical fibers of different materials at micro and nano-scale. This emerging technology is opening the way for the developing of novel miniaturized “all-in-fiber” devices exploitable for...

The presence of ethanol in wine grapes is an important parameter for the evaluation of their quality in winemaking. In this study we report the development of an amperometric biosensor for the determination of ethanol in must grape based on the alcohol dehydrogenase enzyme immobilized on polyaniline doped with poly(2-acrylamido-2-methyl-1-propane)...

Optical fibers technology has experienced a tremendous growth and advancement over the past several decades, not only in transmission systems for communications (where nowadays totally dominate especially at the high performances level) but also in the sensing field [1]. For this reason, there is an ever increasing need to add new functionalities a...

We report the evidence of plasmonic-photonic resonances in hybrid metallo-dielectric quasi-crystal nanostructures composed of aperiodically- patterned low-contrast dielectric slabs backed on a metal layer. Via both experimental and numerical studies, we analyze the resonant phenomena with specific reference to the Ammann-Beenker octagonal tiling ge...

We have recently demonstrated a valuable fabrication path for the integration and patterning of functional materials at micro and nano-scale onto optical fibers, posing the basis for a new and emerging technological vision named “Lab on Fiber”. This process has been validated through the realization, directly onto the fiber tip, of 2D metallo-diele...

In this work, we present a simple fabrication process enabling the integration of a subwavelength amorphous silicon layer inside optical fibers by means of the arc discharge technique. To assess our method, we have fabricated a compact in-line Fabry–Perot interferometer consisting of a thin ( < 1 μm ) a-Si:H layer completely embedded within a stand...

We report on a reliable fabrication process enabling the integration of dielectric and metallic nanostructures on the tip of optical fibers. The proposed fabrication procedure involves conventional deposition and nanopatterning techniques, typically used for planar devices, but here adapted to directly operate on optical fiber tip. We fabricate and...

We have recently proposed a valuable fabrication route for the integration and patterning of functional materials at nanoscale onto optical fibers, posing the basis for a new technological vision named “Lab-on-Fiber”. The validation of the proposed process has been carried out through the realization, directly onto the fiber tip, of 2D metallo-diel...

“Lab-on-Fiber” technology is an emerging field envisioning a novel class of advanced, multifunctional photonic devices and components arising from the integration onto optical fibers of different materials at micro and nano-scale with suitable physical, chemical and biological properties. This new fascinating and intriguing research field thus prop...

In this chapter, we report on recent numerical and experimental results obtained with Fiber Bragg Grating (FBG) hydrophones for underwater acoustic detection. The optical hydrophones under investigation consist of FBGs coated with ring-shaped polymers of different size. Via fullwave numerical simulations, we study the complex opto-acoustomechanical...

Sensing schemes based on Rayleigh anomalies (RAs) in metal nanogratings exhibit an impressive bulk refractive-index sensitivity determined solely by the grating period. However, the surface sensitivity (which is a key figure of merit for label-free chemical and biological sensing) needs to be carefully investigated to assess the actual applicabilit...

This work provides numerical and experimental evidence that a significant difference exists between bulk and surface sensitivities in nanodevices based on Rayleigh anomalies (RAs) when employed for sensing the surrounding refractive index. In particular, recently proposed sensing schemes based on RAs in optical nanogratings are shown to be applicab...

We recently introduced a reliable fabrication process enabling the integration of dielectric and metallic nanostructures directly on the tip of optical fibers, involving conventional deposition and nanopatterning techniques suitably adapted to directly operate on the fiber tip1. By using this approach, we also demonstrated a first technological pla...

We recently introduced a reliable fabrication process enabling the integration of dielectric and metallic nanostructures directly on the tip of optical fibers1. It involves conventional deposition and nanopatterning techniques (typically used for planar devices fabrication) suitably adapted to directly operate on the fiber tip. By using this approa...

In this work, an ultra compact in line fiber optic Fabry-Perot interferometer is presented. The interferometric structure consists of a thin (< 1 μm) amorphous silicon layer in line integrated into a standard single mode optical fiber by means of an electric arc discharge technique. The device exhibits low loss (1.46 dB) and high interference fring...

A growing demand for low-alcohol drinks, due to health and social benefits resulting from lower alcohol consumption, has given rise to the development of techniques for alcohol reduction or elimination in beverages. The main difficulty is the development of a low alcohol content product with sensory properties similar to the original one. This work...

The first evidence of out-of-plane resonances in hybrid metallo-dielectric quasi-crystal (QC) nanostructures composed of metal-backed aperiodically patterned low-contrast dielectric layers is reported. Via experimental measurements and full-wave numerical simulations, these resonant phenomena are characterized with specific reference to the Ammann-...

We introduce a reliable fabrication process enabling the integration of dielectric and metallic nanostructures on the tip of optical fibers. It involves conventional deposition and nanopatterning techniques typically used for planar devices, but here adapted to directly operate on optical fiber tip. Following this approach, we demonstrate a first t...

We propose a reliable fabrication process enabling the integration of dielectric and metallic nanostructures on the tip of optical fibers, thus representing a further step in the "lab-on-fiber" technology roadmap. The proposed fabrication procedure involves conventional deposition and nanopatterning techniques, typically used for planar devices, bu...

We report the evidence of plasmonic-photonic resonances in hybrid metallo-dielectric quasi-crystal nanostructures composed of aperiodically-patterned low-contrast dielectric slabs backed on a metal layer. Via both experimental and numerical studies, we characterize these resonant phenomena with specific reference to the Ammann-Beenker (quasiperiodi...

We report the design, fabrication and characterization of a 2D hybrid metallo-dielectric photonic crystal (PC) nanostructure, directly realized by innovatively applying the electron beam lithography technique on the cleaved end face of a standard single mode optical fiber (SMF). In our configuration, the PC is illuminated in the out-of-plane direct...

We report the first evidence of out-of-plane resonances in hybrid metallo-dielectric quasi-crystal nanostructures composed of metal-backed aperiodically-patterned low-contrast dielectric layers. We numerically and experimentally characterize these resonant phenomena and investigate the underlying physics. We show that, by comparison with standard p...

PART ONE: The "Lab on Fiber" concept envisions novel and highly functionalized technological platforms completely integrated in a single optical fiber that would allow the development of advanced devices, components and sub-systems to be incorporated in modern optical systems for communication and sensing applications. The realization of integrated...

PART ONE: The "Lab on Fiber" concept envisions novel and highly functionalized technological platforms completely integrated in a single optical fiber that would allow the development of advanced devices, components and sub-systems to be incorporated in modern optical systems for communication and sensing applications. The realization of integrated...

By now long-period fiber gratings (LPFGs) represent a well-assessed in-fiber technology. Their peculiar spectral properties and the intrinsic surrounding refractive index (SRI) sensitivity, together with the well known advantages of optical fibers, make these structures one of the most powerful tools, especially in the sensing field. Unfortunately,...

The "Lab on Fiber" concept envisions novel and highly functionalized technological platforms completely integrated in a single optical fiber that would allow the development of advanced devices, components and sub-systems to be incorporated in modern optical systems for communication and sensing applications. The realization of integrated optical f...

Amperometric screen printed nitrate reductase by Escherichia coli biosensors have been developed to detect nitrate ions. The effects of two different immobilization procedures of NaR and mediator (Azure A and Methyl viologen MV) to increase the performances (response time, sensitivity, stability) of the nitrate sensor have been studied. The best pe...

Long-period fiber gratings (LPFGs) represent an attractive fiber grating-based technological platform because of their selective spectral features together with the intrinsic sensitivity to surrounding refractive index (SRI). Unfortunately, their main limitation relies on the necessity to opportunely coat the glass substrate when sensitivity enhanc...

The feasibility of exploiting novel chemo-sensitive coatings based on cadmium arachidate (CdA)/single-walled carbon nanotube (SWCNT) composites for the development of high performance optical chemo-sensors has been experimentally investigated and proved. SWCNT nano-composite overlays have been transferred on the distal end of standard optical fiber...

The effects of charge transfer induced by analyte molecule adsorption on the sensing properties of single-walled carbon nanotube (SWCNT) fiber optic chemical nano-sensors has been investigated. Experimental evidence indicates that extrinsic fiber optic Fabry–Perot (FP) interferometers incorporating nano-scale sensitive layers of SWCNTs and cadmium...

In this contribution, the use of novel nanocoatings composed of single-walled carbon nanotubes (SWCNTs) embedded in Cadmium Arachidate (CdA) matrixes is proposed to improve the typical low adhesion of carbon nanotubes to the surface of standard optical fibers, thus enabling the development of highly sensitive, reliable and robust SWCNT-based fiber...

Recent preliminary studies have demonstrated the feasibility of using Single-Walled Carbon Nanotubes (SWCNTs) as sensitive coatings of optical fiber sensors for the detection of chemical traces in water at room temperature. A low-finesse extrinsic Fabry-Perot configuration was adopted as sensing scheme and Langmuir-Blodgett thin SWCNT films have be...

In this work, the feasibility of exploiting novel Cadmium Arachidate (CdA)/single-walled carbon nanotubes (SWCNTs) based composites as sensitive coatings for the development of robust and high performances optoelectronic chemosensors able to work in liquid environments has been investigated and proved. Here, nano-composite sensing layers have been...

In this letter, the possibility to use single-walled carbon nanotubes (SWCNTs) as sensitive nanostructured material for the development of an optoelectronic sensor that can perform chemical detection in water has been investigated and demonstrated for the first time. The fabricated sensor has been employed in a reflectometric system involving singl...

In this work, the feasibility to exploit optoelectronic chemo-sensors based on cadmium arachidate (CdA)/single-walled carbon nanotubes (SWCNTs) composites for detection of chemical pollutants both in air and water environments has been investigated. The nanocomposite sensing layers have been transferred upon the distal end of standard optical fiber...