Romeo Bernini

Italian National Research Council | CNR · Institute for Electromagnetic Sensing of the Environment IREA

A distributed optical fiber system for spectrophotometric analysis of liquid samples based on light diffusing fiber (LDF) is presented. The sensor is based on a high-density white light emitting diode (LED) strip, which is side coupled to a glass based light-diffusing fiber (LDF) that acts as distributed optical receiver. The light emitted from a s...

In order to complete this set of three companion papers, in this last, we focus our attention on environmental monitoring by taking advantage of photonic technologies. After reporting on some configurations useful for high precision agriculture, we explore the problems connected with soil water content measurement and landslide early warning. Then,...

In this work, we demonstrate a novel mechanism to localize the stimulated Brillouin interaction over a specific portion of an optical fiber, using a Brillouin Optical Frequency-Domain Analysis (BOFDA) interrogation system and an array of tapers. We show, both numerically and experimentally, that the frequency-domain fiber response, acquired over a...

Our group, involving researchers from different universities in Campania, Italy, has been working for the last twenty years in the field of photonic sensors for safety and security in healthcare, industrial and environment applications. This is the first in a series of three companion papers. In this paper, we introduce the main concepts of the tec...

The employability of photonics technology in the modern era’s highly demanding and sophisticated domain of aerospace and submarines has been an appealing challenge for the scientific communities. In this paper, we review our main results achieved so far on the use of optical fiber sensors for safety and security in innovative aerospace and submarin...

In this manuscript, we demonstrate that an array of tapers, consecutively formed along a single-mode optical fiber, can be used to realize a localized, dynamic strain sensing position with a Brillouin Optical Frequency-Domain Analysis (BOFDA) sensor. The multi-taper realizes a periodic modulation of the Brillouin frequency shift, which appears as a...

We demonstrate the use of a network analysis optical frequency domain reflectometer for dynamic and distributed vibration sensing. Two configurations are assessed and compared, based on either double sideband or single sideband modulation.

In this paper, we demonstrate the use of a network analysis optical frequency domain reflectometer (NA-OFDR) for distributed vibration sensing at a spatial resolution of ' 3 cm and an acquisition rate up to ' 80 Hz. The system makes use of a continuous-wave (CW) laser, whose amplitude is modulated using a vector network analyzer. The latter is also...

An optical fiber sensor system for distributed optical absorption spectroscopy based on light diffusing optical fiber is proposed and evaluated. The sensor is composed by two light-diffusing glass fibers radiatively coupled. The light from a pulsed laser diode propagates along the first fiber and is locally diffused out into the medium between the...

The occurrence of different contaminants in drinking water, surface water, domestic wastewater, and other water sources has led to increased interest in developing new methods and instruments for water quality monitoring able to provide adequate and rapid management interventions. A critical analysis of the main optical spectroscopy techniques for...

We demonstrate the use of non-adiabatic tapers for refractive index sensing in optical fibers based on Brillouin scattering. By exciting higher order optical modes along the taper, the Brillouin gain spectrum becomes multipeaked, where each peak exhibits a different sensitivity to the refractive index of the surrounding medium. By this method, we d...

We report an optofluidic hybrid silicon-polymer planar ring resonator with integrated microfluidic channels for efficient liquid delivery. The device features a planar architecture of intersecting liquid-core waveguides and microfluidic channels. A low-loss integration of microfluidic channels is accomplished by exploiting the interference pattern...

In this paper, we demonstrate that multiple tapers in optical fibers allow for quasi-distributed refractive index sensing via a high spatial resolution Brillouin Optical Frequency-Domain Analysis (BOFDA) configuration. We first characterize, theoretically and experimentally, the variation of the Brillouin frequency shift (BFS) with the diameter of...

The present paper describes a compact point of care (POC) optical device for therapeutic drug monitoring (TDM). The core of the device is a disposable plastic chip where an immunoassay for the determination of immunosuppressants takes place. The chip is designed in order to have ten parallel microchannels allowing the simultaneous detection of more...

The power coupling between two light diffusing multimodal optical fibers of equal and finite lengths that are parallel oriented, and which are coupled through scattering processes, is investigated both theoretically and experimentally. In particular, a simple analytical model of the inherent coupling coefficient, derived according to a perturbation...

A portable sensor for fluorescence spectroscopy of liquids has been developed. This sensor exploits the autofluorescence produced by organic chemical compounds when exposed to ultraviolet or visible light. In particular, the autofluorescence produced by pigments present in cyanobacteria and microalgae allow their in vivo detection. Liquid jet waveg...

A full polymeric optofluidic Fabry–Perot (FP) resonator with a high quality factor (Q) is proposed and tested. The device is based on multilayer optical polymeric films that act as high reflectivity interference mirrors. The all-polymeric laminated structure avoids any deposition or etching process, simplifying the fabrication procedure while retai...

A continuous liquid level fiber optic sensor has been devised, developed, and tested. The sensor is based on two coupled light-diffusing glass fibers. The light from a laser diode is diffused out from the first fiber by scattering and coupled, always by the scattering, to the second fiber. The working wavelength has been selected in order to be str...

An analytical technique allowing a distinction between cyanobacteria and other microscopic life forms that exploits autofluorescence in the deep ultraviolet has been developed. The proposed approach is based on the amplitude of relative fluorescence peaks of natural pigments or metabolites in unicellular microorganisms commonly present in the water...

The deep ultraviolet fluorescence characteristics of several cyanobacteria and microalgae are analyzed and exploited for their discrimination in liquid samples. The proposed approach is based on relative fluorescence peak amplitude of natural pigments in cyanobacteria or other planktonic species commonly present in water bodies. The experimental re...

Filtering strategies are a crucial aspect for signal detection in many fluorescence based systems such as chemical and/or biochemical sensors. Here we present the design, fabrication and characterization of a new waveguide absorption filter capable of maximizing the fluorescence signal collection thanks to its high numerical aperture. The compariso...

Smart cities are getting essential to drive economic growth, increase social prospects and improve high-quality lifestyle for citizens. To meet the goal of smart cities, Information and Communications Technology (ICT) have a key role. The application of smart solutions will allow the cities to use ICT and big data to improve infrastructure and serv...

An integrated full polymeric sensing platform composed by a self-assembled bottle microresonators packaged with planar waveguide in a stable structure is presented. Microbottles made of SU-8 resist and NOA resins have been fabricated and characterized. The interrogation system is constituted by evanescently coupled planar waveguide fabricated in SU...

In this Letter, we demonstrate the possibility to measure the refractive index of a liquid, using the stimulating Brillouin scattering in a 3-cm-long side-polished optical fiber. In addition, we show that by depositing a high-refractive index layer on the polished surface the sensitivity of the Brillouin frequency shift (BFS) can be increased due t...

Whispering Gallery Mode (WGM) micro-resonators like microspheres or microtoroids are typically used as high-Q cavity substrate on which a functional film coating is deposited. In order to exploit the coating properties a critical step is the efficient excitation of WGMs mainly contained inside the deposited layer. We developed a simple method able...

Integrated hollow-core antiresonant reflecting optical waveguides are designed and analyzed for mid-infrared propagation. With a proper selection of waveguide materials and geometry, low loss propagation lower than 1.5 dB/cm in the whole 2.5-14 μm range could be achieved. Single mode waveguides, with a modal purity above 95% after propagation lengt...

An all polymeric platform based on planar microring resonator employing a microfluidic flow-through approach is presented and exploited for biosensing applications. A micromilled hole in the center of the microring resonator drives the analyte flow towards the sensing surface, so optimizing the transport kinetic. A simulated and experimental evalua...

Optofluidics, nominally the research area where optics and fluidics merge, is a relatively new research field and it is only in the last decade that there has been a large increase in the number of optofluidicapplications as well as in the number of research groups devoted to the topic. Nowadays optofluidics applications include, without being lim...

A multifunctional lab-on-a-chip platform for spectroscopic analysis of liquid samples based on optofluidic jet waveguide is reported. The optofluidic detection scheme is achieved through total internal reflection arising in a liquid jet of only 150 µm diameter, leading to highly efficient signal excitation and collection. This results in a optoflui...

Infectious diseases and sepsis, as a severe and potential medical condition in which the immune system overreacts and finally turns against itself, are a worldwide problem. As a matter of fact, it is considered the main cause of mortality in intensive care. For such a pathology, a timely diagnosis is essential, since it has been shown that each hou...

A novel therapeutic drug monitoring point of care testing (POCT) optical device for the detection of immunosuppressants in transplanted patients was designed and tested, with the body interface constituted by an intravascular microdialysis catheter (MicroEye®) which provides the dialysate as clinical sample. An optical biochip with 10 microchannels...

An optical fiber fuel level sensor for aeronautical applications is developed and tested. The sensor is based on an array of total internal reflection point sensors multiplexed on a single fiber by optical couplers and simultaneously interrogated by an Optical Time Domain Reflectometry approach. Unlike conventional sensors based on total internal r...

For the detection of chemical agents in different environments, the combination of plastic optical fibers (POFs) and molecularly imprinted polymer (MIP) layers has been tested as a way to obtain a low cost, highly selective and sensitive surface plasmon resonance (SPR) chemical sensor. A novel type of optical chemical sensor based on POF-MIP has be...

We demonstrate a Brillouin optical frequency-domain reflectometry (BOFDR) technique, which can measure the strain and/or temperature along an optical fiber with one-end access, by detecting the spontaneous Brillouin scattering from a sinusoidally modulated pump light. Compared to the Brillouin optical frequency-domain analysis (BOFDA), we show that...

For the detection of chemical agents in different environments, the combination of plastic optical fibers (POFs) and molecularly imprinted polymers (MIPs) receptors has been tested as a way to obtain low cost, highly selective and sensitive optical chemical sensors based on plasmonic resonance. In this work, a novel type of optical chemical sensor...

Brillouin scattering properties of silica fibers at 850 nm wavelength were experimentally investigated using a Brillouin optical time-domain analysis (BOTDA) scheme. In the single-mode 780-HP fiber, the Brillouin frequency shift (BFS) and FHWM of the Brillouin Gain Spectrum were found to be ∼ 19795 MHz and 90 MHz, respectively. The estimated peak B...

The feasibility of water monitoring by Raman spectroscopy with a portable optofluidic system for in-situ applications has been successfully demonstrated. In the proposed approach, the sample under analysis is injected into a capillary nozzle in order to produce a liquid jet that acts as an optical waveguide. This jet waveguide provides an effective...

In this paper, we report the study on a new protocol for the immobilization process of antigen/antibody assay on SU-8 layers by oxygen plasma treatment. Plasma treatments, at different plasma powers and for different duration times, are performed and their effects on immobilization efficiency are studied. The chemical properties and the surface mor...

Polymer micro-bottle resonators are fabricated by means of a simple self-assembling process. High optical quality SU-8 negative resist is chosen as bottle material. SU-8 is dispensed onto a fiber stem and is kept in rotation during the UV photo-polymerization. Micro-bottles with different geometrical sizes have been obtained by changing the SU-8 di...

In this paper, we introduce a liquid core antiresonant reflecting optical waveguide (ARROW) as a novel optofluidic device that can be used to create innovative and highly functional microsensors. Liquid core ARROWs, with their dual ability to guide the light and the fluids in the same microchannel, have shown great potential as an optofluidic tool...

This publisher’s note corrects the author listing of a publication.

In this paper, we analyze numerically the effect of phase noise from the laser in Brillouin optical time-domain analysis (BOTDA) sensors. Due to laser phase noise, the phase shift between pump and probe beams is a stochastic variable with zero mean and variance changing with the position along the fiber. The numerical results, carried out for vario...

We propose a slope-assisted Brillouin sensing scheme based on the interaction between a phase modulated probe and a pulsed pump. The modulation frequency of the probe is chosen so that both first-order modulation sidebands lie within the Brillouin gain spectrum generated by the pump field. Owing to stimulated Brillouin scattering (SBS), a phase mod...

This chapter reviews the state-of-the-art microfluidic optical methods for water monitoring and analysis. Microfluidics permits to reduce the system dimension, increasing its analytical speed and sensitivity. It also permits to achieve an unprecedented economy of scale, by dramatically increasing production throughput and reducing individual costs....

An on-chip optofluidic 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 an...

This paper presents a novel sensing polymeric platform based on microring resonators with a direct microfluidic addressing scheme employing a flow-through approach. The fabrication of a hole placed in the centre of the ring allows precise analyte dispensing with an efficient transfer rate to the ring surface. The devices are exploited for biosensin...

Cities are increasingly becoming a focal point for economies and societies at large, particularly because of ongoing urbanisation and the trend towards increasingly knowledge-intensive economies. Cities need to change and develop, but this change needs to be achieved in a smart way, making cities " smart cities ". Information & Communication Techno...

In the present work an optimization study on the performances of polymeric ring resonator is reported. An embedded structure, characterized by the presence of an under and upper layer of Su-8 2002, is chosen in order to improve the optical performances, in terms of quality factor and extinction ratio. Specific combinations of Su-8 2002 diluted in c...

A novel fuel level sensor for aeronautical applications is developed. The sensor is based on an array of total internal reflection (TIR) point sensors. Respect to conventional TIR sensors the new design permits to be sensitive to common jet fuels (JetA, JP4,JP7) but also to operate with new alternative fuels. The sensor doesn't require aircraft cal...

Soluble urokinase plasminogen activator receptor (suPAR) is an inflammatory protein present in blood and a marker of disease presence, severity and prognosis. A heterogeneous sandwich assay is proposed for quantifying suPAR by employing a capture antibody from rat and a biotinylated detection antibody from mouse. Optical detection was achieved by a...

In this work we show that integrated Hybrid Silicon-PDMS Antiresonant Reflecting Optical Waveguide (H-ARROW) can be applied for the realization of optofluidic devices. H-ARROW is constituted by the optofluidic channel of a conventional ARROW, sealed with a thin PDMS layer. This layout simplifies the integration of microfluidic parts to manipulate l...

An optofluidic device based on a liquid jet waveguide has been successfully applied in Raman spectroscopy. The sample under analysis is used to produce a liquid stream by means of a capillary nozzle. The waveguiding nature of the stream is used to effectively collect the Raman signal arising from chemical compounds when opportunely excited. An alig...

We report an optofluidic ring resonator sensor based on liquid-core hybrid silicon-polymer waveguides. The device features a planar layout that combines optical and fluidic functions on the same platform. A high quality factor of $1.44, times , 10^{4}$ is achieved. The device resonant wavelength shift has been measured as a function of the water-co...

In this paper we report the performance optimization of an integrated optofluidic ring resonator based on liquid core hybrid Antiresonant Reflecting Optical Waveguide (h-ARROW). Each optical element of the proposed ring has been simulated to find the optimized optical configuration which accomplishes single mode operation and reduced attenuation lo...

In the hospital Intensive Care Units (ICU) there is an even greater demand by the physicians for the continuous immunosuppressant drug monitoring in the transplanted patient therapy, in order to avoid different risks and diseases which may occur as result of some drug dosage related effect, such the rejection crisis or sepsis. Here we present a nov...

An optofluidic sensor based on a liquid jet waveguide has been successfully applied in Raman spectroscopy. The jet waveguide is obtained by ejecting the solution under analysis through a capillary nozzle. A self-aligned configuration allows to couple the liquid waveguide with an optical probe consisting of two optical fiber respectively used to exc...

A novel optical biochip for immunosuppressants detection in transplanted patients is described. The optical working of the chip, based on total internal reflection fluorescence and consisting of two bonded polymeric parts, a Zeonex 330 slide and a Topas foil was demonstrated. In parallel, a heterogeneous competitive immunoassay for tacrolimus was i...

Optofluidics is a relatively young research field able to create a tight synergy between optics and micro/nano-fluidics. The high level of integration between fluidic and optical elements achievable by means of optofluidic approaches makes it possible to realize an innovative class of sensors, which have been demonstrated to have an improved sensit...

In this work we report the performance optimization of an integrated optofluidic ring resonator (ORR) based on liquid core hybrid antiresonant reflecting optical waveguides (h-ARROWs). We show that with an accurate design of each optical elements of the proposed ring, quality factor up to 1.4×104 can be achieved.