PUBLICATIONS
Bellone, Aurora; Olivero, Massimo; Vallan, Alberto; Perrone, Guido
Photonics West - 2023
DOI / Linkabstract
The paper presents the development and investigation of distributed and a quasi-distributed fiber optic sensors for the real-time monitoring of radiations during cancer treatments. Both sensors rely on ad-hoc developed nanoparticle-doped optical fibers with enhanced sensitivity to radiation. The distributed sensor is interrogated with an OFDR-based instrument and allows the reconstruction of the spatial dose distribution along the fiber. The quasi-distributed sensor is implemented through fiber Bragg gratings inscribed with a femtosecond laser in the few-mode section of a single mode-multi mode-single mode interferometer.
Bellezza Prinsi, Chiara; Iannucci, Leonardo; Olivero, Massimo; Grassini, Sabrina; Vallan, Alberto; Perrone, Guido
PROGRESS IN BIOMEDICAL OPTICS AND IMAGING
DOI / Linkabstract
Monitoring pH is crucial across many fields due to its significant impact on chemical reactions, biological processes, and environmental conditions. While traditional pH measurement methods are limited to occasional use or require expensive and cumbersome equipment for continuous monitoring, the paper presents the preliminary study for a compact, cost-effective, and real-time photonic system for the early detection of pH variations in fluids. The detection is based on pH-induced changes in organic dyes fluorescence. The results on strongly alkaline pH are discussed under different environmental conditions.
Bellezza Prinsi, Chiara; Perrone, Guido
Photonics West
DOI / Linkabstract
The paper presents the realization of a prototype of a compact, cost-effective, and real-time photonic system for the early detection of quality variations in flowing water and for its sanitization. The detection is based on a multi-functional fiber Surface Plasmon Resonance (SPR) sensor, while the disinfection is obtained with a combination of short-wavelength light in the UV-blue region.
Serafini, Valentina; Riva, Martina; Mirigaldi, Alessandro; Perrone, Guido
Proc. SPIE 11668, High-Power Diode Laser Technology XIX, 116680J - 2025
DOI / Linkabstract
Blue laser diode sources have already proved to be an effective alternative for material processing, especially of high reflective materials, such as copper; now the challenge is to increase their power while improving brightness and reducing the cost-per-watt. The paper presents the development of a family of blue laser modules that, making use of the same platform and assembly lines of similar 9xx nm modules, can achieve an unprecedented combination of power, brightness, compactness and cost reduction. These modules rely on a proprietary architecture to combine a plurality of chips through spatial and polarization multiplexing, obtaining up to 100W of output power in a 100 μm fiber. Preliminary experimental results for module making use of spatial multiplexing report 35W output power in a 50 μm fiber.
Olivero, Massimo; Perrone, Guido;
SENSING AND BIO-SENSING RESEARCH - 2024
DOI / Linkabstract
In this work, we present the detection of proteins expressed by poxvirus with fiber-optic probes based on a semi-distributed interferometer (SDI) assisted by a fiber Bragg grating (FBG), performing the measurement directly into a wastewater sample. Modern biosafety applications benefit from real-time, dynamic-sensing technologies that can perform diagnostic tasks into a wide set of analytes, with a particular emphasis on wastewater, which appears to collect a significant number of viral titers in urban and indoor environments. The SDI/FBG probe can perform substantial progress in this field, as it embeds a dual sensitivity mechanism to refractive index changes (sensitivity up to 266.1 dB/RIU (refractive index units)) that can be exploited in biosensing, while simultaneously having the capability to measure the temperature (sensitivity 9.888 pm/°C), thus providing an intrinsic cross-sensitivity compensation. In addition, a standard FBG analyzer can be used as an interrogator, improving affordability and real-time detection over previous works. The probes have been functionalized with antibodies specific for L1, A27 and A33 vaccinia virus proteins, performing detection of a protein concentration in a scenario compatible with online viral threat detection. Direct detection of wastewater samples shows that the L1-functionalized sensor has a higher response, 9.1–11.3 times higher than A33 and A27, respectively, with a maximum response of up to 1.99 dB and excellent specificity. Dynamic detection in wastewater shows that the sensors have a response over multiple detection cycles, with a sensitivity of 0.024–0.153 dB for each 10-fold increase of concentration.
Maryam Firuzalizadeh; Rossella Gaffoglio; Giorgio Giordanengo; Marco Righero; Marcello Zucchi; Aurora Bellone; Alberto Vallan; Guido Perrone; Giuseppe Vecchi
Proceedings of the 2024 COMSOL Conference - 2024
Olivero, Massimo; Mirigaldi, Alessandro; Serafini, Valentina; Vallan, Alberto; Perrone, Guido; Tosi, Daniele
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT - 2021
DOI / Linkabstract
This article reports on the first demonstration of in situ, real-time dosimetry realized with an enhanced backscatttering optical fiber, and a high resolution optical backscattering reflectometry measurement. This work is devised to overcome the current problems in monitoring radiotherapy treatments, in particular, the difficult evaluation of not only the actual X-ray dose that is accumulated on the target volume but also the distribution profile of the ionizing radiation beam. Overall, the research aims at developing a dose sensor with the most demanding features of small form factor, spatial profiling, and remote interrogation. The experiments have been conducted by evaluating the spatial profile of radiation-induced spectral shift of the Rayleigh backscattering along an optical fiber exposed to X-rays. The sensing element is a section of specialty optical fiber whose Rayleigh backscattering signature changes under ionizing radiation. The specialty fiber is designed to exhibit an enhanced backscattering, in order to overcome the poor sensitivity to radiation of standard optical fibers that are normally, used in telecommunications. The enhanced sensitivity is achieved by doping the core with either aluminum or magnesium nanoparticles, and two different fibers have been fabricated and tested. The experimental results show the capability of real time detection of the radiation profile from high-dose rates (700 Gy/min) to low-dose rates (2 Gy/min). Moreover, different sensing mechanisms and responses to high- and low-dose rates are evidenced. A comparison with a quasi-distributed sensing system based on an array of fiber Bragg gratings (FBGs) is discussed, highlighting the superior performance of the backscattering approach in terms of sensitivity and spatial resolution, whereas the array of FBGs exhibits an advantage in terms of sampling speed.
Barzan, Giulia; Perrone, Guido;
NANOMEDICINE - 2021
DOI / Linkabstract
Bellone, Aurora; Perrone, Guido;
MATERIALS TODAY CHEMISTRY - 2025
DOI / Linkabstract
Covellite (CuS) nanoparticles (NPs) are versatile, non-noble metal plasmonic materials which have been recognized as promising candidates for therapeutical applications. However, the poor chemical stability of CuS NPs in aqueous media makes their use in medical applications challenging. While the application of coatings to reduce NPs degradation has been successfully proposed for other materials, in the case of CuS this strategy is limited by the loss of the plasmonic performance due to NPs chemical instability in the post-synthesis treatments. In the present study, we successfully obtained core-shell CuS-C nanocomposites with tailored size, enhanced stability, and superior photothermal performance, by applying a novel green synthetic strategy using water as solvent. CuS NPs were synthetized using polyvinylpyrrolidone (PVP) as stabilizer; in addition, a PVP concentration-dependent tunability of size and plasmon wavelength was demonstrated. The carbon shell was generated via hydrothermal carbonization without compromising the plasmonic performance of CuS NPs (52 % of photothermal conversion efficiency) and without inducing aggregation through a strict control of the dissolution/degradation process. The carbon coating slowed down the degradation of CuS NPs in biological fluids without inhibiting the redox activity evaluated as a generation of hydroxyl radicals by electron paramagnetic resonance spectroscopy. When tested in vitro for their cytotoxicity toward mesenchymal stem cells CuS@C appear non cytotoxic after 24 h of incubation up to 100 μg/mL. Moreover, the carbon shell inhibited the pro- proliferative effect observed for CuS NPs at low concentration after 48 h. Overall, the results prove the great potential of CuS-C nanocomposites as photothermal agents for cancer treatments.
BELLEZZA PRINSI, CHIARA; Buscaglia, Paola; Olivero, Massimo; Re, Alessandro; Grassini, Sabrina; Vallan, Alberto; Perrone, Guido
MEASUREMENT SCIENCE & TECHNOLOGY - 2025
DOI / Linkabstract
This study investigates the accuracy of a budget Optical Coherence Tomography (OCT) for measuring the thickness of protective varnishes on ancient artifacts that have to undergo cleaning or restoration. Two sets of glass slides, deposited with layers that mimic the structure of ancient handcraft objects (pigment and varnish), are analyzed. OCT measurements are compared with coating thickness gauge and destructive Scanning Electron Microscope (SEM) analysis. The results show that OCT provides reasonably accurate thickness measurements, with errors significantly lower than typical variability in cultural heritage applications. This suggests even a low-cost OCT has the potential to become a valuable non-invasive tool for real-time monitoring of cleaning treatments on ancient artifacts.
Firuzalizadeh, Maryam; Gaffoglio, Rossella; Giordanengo, Giorgio; Righero, Marco; Zucchi, Marcello; Bellone, Aurora; Vallan, Alberto; Perrone, Guido; Vecchi, Giuseppe
19th European Conference on Antennas and Propagation - 2025
Riva M.; Perrone G.
PROCEEDINGS OF SPIE, THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING - 2020
DOI / Linkabstract
Blue laser diodes are emerging as the next revolution in laser material processing, especially for high reflective materials, such as copper and gold. The paper presents the most recent evolution of a family of medium-high power and high brightness devices specifically conceived for micro-machining applications. The modules make use of a proprietary architecture based on the combination of commercial laser diodes in TO9 package. The diodes are first organized in rows staggered along the fast axis, then the rows are multiplexed along the fast axis; finally, wavelength and polarization multiplexing are exploited to achieve up to 100W of power into a 50 μm/0.22NA fiber.
Serafini, Valentina; Perrone, Guido
Photonics West - SPIE LASER - 2025
DOI / Linkabstract
Blue laser diodes, with their short emission wavelength, are revolutionizing laser material processing, particularly for metals such as copper and gold. Achieving power levels suitable for industrial applications requires the combination of multiple lower-power sources while preserving high beam quality. The paper presents the design a preliminary characterization of a high-brightness laser source for Direct Energy Deposition (DED) processes capable of delivering up to 500 W leveraging on a two-wavelength spectral multiplexing approach. In first experimental tests at up to 300 W a Beam Parameter Product (BPP) of 7.7 mm mrad was measured, resulting in a record brightness of approximately B =510 000 W/m2·sr, which is already well-suited to open new possibilities in the DED processes with high-reflective metals. Furthermore, the system showed the potential to scale up to B = 850 000 W/m2·sr when the sources at the two wavelengths will be operated at full power.
Mirigaldi A.; Serafini V.; Perrone G.
High-Power Diode Laser Technology XXI - 2023
DOI / Linkabstract
The paper reports on the wavelength stabilization of high-power laser diode multi-emitter modules using as the external reflectors fiber Bragg gratings that are directly inscribed into the large mode area module delivery fiber using a femtosecond laser. Experiments have been carried out in a 200 μm fiber at 976 nm, but the approach can be extended at other fiber diameters and wavelengths. The results have demonstrated an effective stabilization over a broad driving current range, with power penalties in line or slightly lower than those of more traditional architectures that make use of discrete components, such as volume Bragg gratings, but with the advantage of not requiring the alignment of additional elements.
Bellone Aurora; Perrone Guido;
NANOSCALE ADVANCES - 2025
DOI / Linkabstract
Hydrothermal carbonization (HTC) of carbohydrates has been reported as a sustainable and green technique to produce carbonaceous micro- and nano-materials. These materials have been developed for several applications, including catalysis, separation science, metal ion adsorption and nanomedicine. Carbon nanoparticles (CNPs) obtained through HTC are particularly interesting for the latter application since they exhibit photothermal properties when irradiated with near-infrared (NIR) light, act as an antioxidant by scavenging reactive oxygen species (ROS), and present good colloidal stability and biocompatibility. However, due to the highly disordered structure, there is still a poor understanding of the mechanism of synthesis of CNPs. Consequently, the modulation of the CNP properties by controlling the synthetic parameters is still a challenge. In this work, a novel and simplified HTC synthetic strategy to obtain non-aggregated glucose derived CNPs in the 15–150 nm size range with precise control of the diameter is presented, together with an advance in the understanding of the reaction mechanism behind the synthesis. Modifications of the synthetic parameters and a post-synthesis hydrothermal process were applied to increase the bulk order of CNPs, resulting in an increase of the photothermal and ROS scavenging activities, without affecting the morphological and colloidal properties of the nanomaterial.
Massimo Olivero; Aurora Bellone; Martha Segura; Guido Perrone
Conference 12142 Fiber Lasers and Glass Photonics: Materials through Applications III
DOI / Linkabstract
Enhanced Rayleigh backscattering optical fibers, interrogated by an optical frequency domain reflectometer, are used to perform remote real-time measurements of X-ray irradiation profiles, with possible application as dosimeters in radiotherapy treatments. The enhanced Rayleigh backscattering is obtained by proper engineering of the composition of fiber core, either by introduction of Aluminum or Magnesium silicate nanoparticles as radiation-sensitive dopants. A detectable radiation-induced refractive index change can be spatially resolved through the measurement of the frequency shift of the Rayleigh backscattering along the fiber. It is experimentally demonstrated that two mechanisms of radiation-induced refractive index change take place. At doses nearly compatible with those delivered in radiotherapy, a negative refractive index is induced, whereas at high doses the change is positive. This behavior is also confirmed by the shift of Bragg wavelength of a fiber Bragg grating inscribed in the nanoparticles-doped fiber and used as a reference.
Firuzalizadeh, Maryam; Gaffoglio, Rossella; Giordanengo, Giorgio; Righero, Marco; Zucchi, Marcello; Bellone, Aurora; Vallan, Alberto; Perrone, Guido; Vecchi, Giuseppe
CANCERS - 2025
DOI / Linkabstract
Objective: Microwave hyperthermia is a clinically proven cancer treatment used in combination with conventional therapies to enhance the overall treatment outcome. It consists in selectively increasing the temperature of tumor cells to 40–44 °C by means of electromagnetic fields that are externally generated and coupled to the patient body via antenna applicators. The primary goal is to shape the power deposition (specific absorption rate, SAR) with focusing on the tumor region, and minimizing the risk of hotspots in the surrounding healthy tissues. Methods: For non-superficial tumors, phased-array antennas are used to focus the energy on the tumor. Finding patient-specific optimal antenna feeding coefficients represents an essential step to ensure an effective and safe administration of the heating. In this article, we present a way to optimize the array power transfer effectiveness (impedance matching) that does not deteriorate the spatial power deposition performance. A global optimization approach is adopted, using a cost function properly tailored to incorporate the active reflection coefficients of the array and the Hotspot-to-Target SAR Quotient (HTQ)—the latter being the standard in hyperthermia applications. Results: The effectiveness of the technique is demonstrated in a scenario relevant to the treatment of tumors in the neck region. The results show that our method significantly improves antenna matching without compromising the HTQ, achieving values within the recommended limits. The performance of the proposed approach is also experimentally tested with full heating in a corresponding phantom. Conclusions: This study introduces an optimization approach that enhances phased-array antenna performance for hyperthermia treatments without affecting spatial power deposition.
Bellone A.; Olivero M.; Coppa G.; Vallan A.; Perrone G.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
DOI / Linkabstract
The optimization of laser ablation surgical procedures – specifically for the treatment of tumors – requires evaluating the temperature distribution across the entire area under treatment (e.g., the tumor volume). However, minimally invasive temperature sensors can only provide information in a limited number of points. Therefore, an effective prediction algorithm is required to reconstruct the temperature map for the entire heat affected tissue from as few temperature measurements as possible. This work presents an approach for predicting the temperature around the laser delivery fiber, based on the thermal Green’s function, where patient-specific tissue thermal parameters are obtained through a fitting procedure using measurement of the temperature evolution at known locations. The proposed method is independent of the specific temperature sensor used; in the experiments reported, temperature was measured both at the prediction points and at validation points using quasi-distributed sensor composed of dense fiber Bragg grating (FBG) arrays, written with a femtosecond laser. A preliminary validation under ideal conditions, represented by ex-vivo cases, has been performed through a series of experiments on bovine liver samples. The obtained results demonstrate that it is possible to predict the temperature distribution across the entire ablated area, with errors well below the commonly accepted uncertainty for treatments of this type.
Serafini, Valentina; Bellezza Prinsi, Chiara; Bellone, Aurora; Perrone, Guido
PROGRESS IN BIOMEDICAL OPTICS AND IMAGING - 2025
DOI / Linkabstract
The paper presents the design and preliminary experimental validation of a fiber laser with direct emission in the yellow, which has been developed within the “Yellow-FLiCkEr”project, funded by the Italian Ministry of University and Research. The laser uses Dy-doped soft-glass fibers, both commercial and ad-hoc custom made. The pump is provided by high-power blue laser diodes and the mirrors are Bragg gratings directly inscribed in the soft-glass fiber with a femtosecond laser. Suitable models have been developed both to optimize the laser behavior and to study the laser-eye tissue interaction. Preliminary studies with cultivated cells have demonstrated the laser’s potential for ophthalmology.
Prinsi, Chiara Bellezza; Buscaglia, Paola; Olivero, Massimo; Grassini, Sabrina; Vallan, Alberto; Perrone, Guido
CONFERENCE PROCEEDINGS - IEEE INSTRUMENTATION/MEASUREMENT TECHNOLOGY CONFERENCE - 2024
DOI / Linkabstract
Optical Coherence Tomography (OCT) is an imaging technique commonly used in the biomedical field to obtain below the surface pictures of the tissues. Being a non-contact, fast, and non-invasive method, it can also support conservators during cleaning treatments of painted ancient artifacts. The paper analyzes the reliability of the estimation of the protective varnish thickness from OCT images. Several samples made of Paraloid® B72, a protective material commonly used in conservation, applied on Egyptian blue painting were realized and characterized in comparison with scanning electron microscope images, which is the ultimate tool of conservators to assess the composition and morphology of the surface of artifacts. The results proved to be very promising as the two techniques led to compatible results, demonstrating that OCT can become a routine tool for online monitoring of cleaning treatments.
Olivero, Massimo; Bellone, Aurora; Bano, Andon; Vallan, Alberto; Perrone, Guido
Frontiers in Sensors - 2022
DOI / Linkabstract
Single mode-Multimode-Single mode (SMS) sensors have been attracted a relevant attention because of their simple manufacturing, their capability of sensing different quantities, and their enhanced sensitivity compared to the most common fiber optic sensor represented by Fiber Bragg Gratings (FBGs). Moreover, SMS sensors exhibit blue-shift sensitivity to strain, opposite to FBGs, making them suitable in applications where strain-temperature cross-sensitivity may be an issue. SMS sensors are made by splicing a short multimode, preferably a two mode or quasi two-mode, optical fiber jumper between single mode pigtails. The interference of the modes propagating at different phase velocities produces a spectral pattern that shifts with temperature, strain or any perturbation of the phase difference among the modes. In this paper we review the main features of SMSs as temperature sensors and we present a potential biomedical application in an all-fiber flowmeter based on the hot-wire principle: a fiber-coupled laser source at 980 nm is used as a controllable heating source of the SMS sensor that, when immersed in fluid flow, converts the temperature variation, caused by the heat removal, into a wavelength shift of the transmitted spectrum. Thermal characterization and proof-of-concept experiments show the feasibility and functionality of the sensor and provide an outlook on possible developments and potential applications.
Barbero, Francesco; Gul, Shagufta; Perrone, Guido; Fenoglio, Ivana
TECHNOLOGY IN CANCER RESEARCH & TREATMENT - 2023
DOI / Linkabstract
The diagnosis and treatment of cancer are continuously evolving in search of more efficient, safe, and personalized approaches. Therapies based on nanoparticles or physical stimuli-responsive substances have shown great potential to overcome the inherent shortcomings of conventional cancer therapies. In fact, nanoparticles may increase the half-life of chemotherapeutic agents or promote the targeting in cancer tissues while physical stimuli-responsive substances are more effective and safer with respect to traditional chemotherapeutic agents because of the possibility to be switched on only when needed. These 2 approaches can be combined by exploiting the ability of some inorganic nanomaterials to be activated by light, ultrasounds, magnetic fields, or ionizing radiations. Albeit the development of stimuli-responsive materials is still at the early stages, research in this field is rapidly growing since they have important advantages with respect to organic nanoparticles or molecular substances, like higher stability, and higher efficiency in converting the stimulus in heat or, in some cases, reactive oxygen species. On the other hand, the translation process is slowed down by issues related to safety and quality of the formulations. This literature review summarizes the current advancements in this research field, analysing the most promising materials and applications.
Mirigaldi, Alessandro; Serafini, Valentina; Perrone, Guido
PROCEEDINGS OF SPIE, THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING - 2020
DOI / Linkabstract
A family of laser diode modules emitting hundreds of watt and based on intrinsically wavelength stabilized narrow linewidth high-power Distributed Bragg Reflector (DBR) chips has been manufactured and fully characterized. The module layout exploits a proprietary architecture to combine through spatial and wavelength multiplexing several highly manufacturable chips that integrate a grating and therefore do not require additional external stabilization devices to allow dense wavelength multiplexing. Power levels going from 200W to 400W in a 135 micron core fiber have been achieved using two to four wavelengths. The narrow spectral emission of each chip makes the modules suitable not only for direct-diode material processing, but also for laser pumping.
A. Bellone; M. Olivero; G. Coppa; A. Vallan; G. Perrone
2024 IEEE International Instrumentation and Measurement Technology Conference (I2MTC)
DOI / Linkabstract
The optimization of tumor laser ablation requires the evaluation of the temperature distribution in the tumor volume, but minimally invasive sensors can only provide information in one dimension, and often with consistent errors. Therefore, a suitable prediction algorithm, combined with accurate measurements, are required to reconstruct the temperature map in the tumor mass. This work provides preliminary results on the temperature mapping in an agar-gel phantom, using a quasi-distributed temperature sensor made of a fiber Bragg grating array with improved accuracy, and an algorithm of estimation of the temperature spatial distribution based on the thermal Green’s function. Details on the fabrication and packaging of the sensor are provided along with an experimental evaluation of the thermal diffusivity in the phantom. Furthermore, it is shown how the accuracy on the evaluation of diffusivity is influenced by the synchronization error, which is the delay between the firing of the laser and the temperature acquisition.
Olivero, Massimo; Mirigaldi, Alessandro; Serafini, Valentina; Tosi, Daniele; Vallan, Alberto; Perrone, Guido
2020 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - 2020
DOI / Linkabstract
The paper reports on the first demonstration of in-situ, real-time dosimetry realized with an enhanced back-scattering optical fiber and a high-resolution optical back-scattering reflectometry measurement. This work is devised to overcome the current problems in monitoring radiotherapy treatments, in particular the difficult evaluation of not only the actual x-ray dose that is accumulated on the target volume, but also the distribution profile of the ionizing radiation beam. The experiments have been conducted by evaluating the radiation-induced spectral shift of the Rayleigh back-scattering along the fiber under test during x-ray exposure, in a radiation chamber. The sensing region is a section of aluminum-doped silicate fiber, that overcomes the poor sensitivity to radiation of standard, germanium-doped, silicate fibers for telecom applications. The preliminary results show that it is possible to remotely track the x-ray dose at high dose rates (700 Gy/min) and at rates closer to therapeutic values (22 Gy/min). A linear relationship between accumulated dose and spectral shift has been found. This research aims at developing a dose sensor with the most demanding features of small form factor, spatial profiling and remote interrogation.
Bellone, Aurora; Olivero, Massimo; Perrone, Guido;
SCIENTIFIC REPORTS - 2023
DOI / Linkabstract
In this work, we present the development and biofunctionalization of a fiber-optic ball-resonator biosensor for the real-time detection of vaccinia poxvirus. We fabricated several ball-tip resonators, functionalized through a silanization process to immobilize two bioreceptors: the monoclonal anti-L1R antibody targeting the L1R protein, and the polyclonal rabbit serum antibodies targeting the whole vaccinia virus (VV) pathogen. Experimental measurements were carried out to detect VV in concentrations from 103 to 108 plaque-forming units (PFU), with a limit of detection of around 1.7-4.3 x 103 PFU and a log-quadratic pattern, with a response up to 5 x 10-4 RIU (refractive index units). The specificity was assessed against herpes simplex virus, used as a non-specific control, with the best results obtained with anti-L1R monoclonal antibodies, and through the detection of vaccinia virus/herpes simplex-1 combination. The obtained results provide a real-time viral recognition with a label-free sensing platform, having rapid response and ease of manufacturing, and paving the road to the seamless detection of poxviruses affecting different human and animal species using optical fibers.
Rossella Gaffoglio; Giorgio Giordanengo; Marco Righero; Marcello Zucchi; Maryam Firuzalizadeh; Aurora Bellone; Alberto Vallan; Guido Perrone; Giuseppe Vecchi
NATURE COMMUNICATIONS - 2025
DOI / Linkabstract
Oncological microwave hyperthermia is a clinically proven sensitizer of radio- and chemo-therapies; it acts by selectively increasing the temperature of tumor cells by means of antenna applicators. Its current limitations mostly come from the inability to reliably predict, and hence control, temperature inside the patient during treatment, especially for deep-seated tumors. Simulations are employed in treatment planning, but due to related uncertainties invasive thermometry is necessary, usually via catheters. Being invasive, their use must be minimized and provides very limited spatial information. Here, we demonstrate an approach to obtain 3D temperature information in real time from few measurement points via massive use of high-performance simulations carried out prior to treatment. The proposed technique is tested both in a fully anthropomorphic in-silico scenario, and in an experimental controlled setting. The obtained results demonstrate the potential of the proposed method as a low-cost real-time temperature monitoring technique in cancer hyperthermia. Use with intra-luminal, minimally-invasive catheters is supported by the positive outcome experimentally obtained using data points directly acquired in the trachea-mimicking phantom structure.
Olivero, Massimo; Perrone, Guido
MICROSYSTEM TECHNOLOGIES - 2024
DOI / Linkabstract
We report a reflection based multimode fiber surface plasmon resonance (SPR) sensor utilizing a high index silicon layer between silver metal and sensing medium layer. Theoretical studies have been carried out to optimize the suitable width of material layer to sense refractive index (RI) of the analyte surrounding the optical fiber sensing region using the transfer matrix method. The RI sensitivity of the proposed SPR sensor has been experimentally verified to reach 4774 nm/RIU with figure of merit of 36.07 and resolution of 6.28E-5 at 1.38 RI. Furthermore, the large thermo-optic coefficient and thermal expansion coefficient of the silicon layer has enhanced the experimental temperature sensitivity of the SPR sensor to 1.76 nm/degrees C.
Alessandra Beccaria;Aurora Bellone;Alessandro Mirigaldi;Valentina Serafini;Massimo Olivero;Alberto Vallan;Guido Perrone
OPTICAL FIBER TECHNOLOGY - 2020
DOI / Linkabstract
Optical fiber based sensors capable of measuring temperature distribution over a given length are particularly at- tractive in the biomedical field, especially in the case of real-time monitoring of minimally invasive hyperthermal treatments of tumors, such as laser ablation, given their intrinsic multiplexing along a single fiber span and the unique properties of optical fibers in terms of flexibility, size and electromagnetic compatibility. The paper com- pares two sensing approaches: one is based on an array of Bragg gratings inscribed in the core of a single-mode fiber, the other detects Rayleigh backscattering from an unmodified single-mode fiber using coherent optical frequency domain reflectometry. Following an introduction, which describes the most distinctive features of the two approaches, the paper presents three comparative experiments, each devised to highlight a peculiar aspect of the sensors. In the first experiment the sensors are exposed to various constant temperature distributions to evaluate the uniformity of the readings along the fiber length. In the second experiment, a known temperature profile is generated through an ad hoc setup to evaluate the actual capability of the two approaches to reconstruct the tem- perature distribution. Finally, in the third experiment the two sensors are employed in a simulated tumor laser ablation procedure to measure the temperature distribution in the irradiated area. Both sensors provide results whose error, mainly due to cross sensitivity between temperature and strain, is acceptable for the considered biomedical application.
Gassino, R.; Perrone, G.; Vallan, A.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT - 2020
DOI / Linkabstract
Fiber optics is the elective technology for sensing temperatures in harsh environments. Among the possible exploitable working principles, fiber Bragg gratings are the most widespread implementation for their excellent balance between system complexity and performance. However, despite they are well known and established, so far metrological investigations have been limited to cases in which the sensor is used in uniform temperature conditions. This paper analyzes the response of commercial fiber Bragg gratings employed as temperature sensors in applications that imply large temperature gradients, such as in laser based thermal treatments of solid tumors. A theoretical model of the sensor is implemented first and then used to evaluate its response in non-uniform temperature distributions. The model results are experimentally validated by means of a liver phantom and comparisons between different grating configurations, such as single or multiplexed with different lengths, are made.
Aurora, Bellone; Chiara, Bellezza-Prinsi; Valentina, Serafini; Roberta, Mulas; Gianni, Coppa; Alberto, Vallan; Guido, Perrone
SPIE BiOS, 2024
DOI / Linkabstract
The paper discusses all-fiber applicators for the percutaneous laser ablation of tumors, which integrate very dense fiber Bragg grating arrays to add quasi-distributed sensing capabilities. First an assessment of the temperature map distribution reconstruction from the measurements is presented and the impact of some non-idealities is studied; then the developed probes are used to analyze different laser operating conditions, comparing the measurements in ex-vivo porcine livers with modeling expectations.
Perrone, Guido; Mirigaldi, Alessandro;
OPTICS EXPRESS - 2021
DOI / Linkabstract
Increasing the number of laser beams that can be coherently combined requires accurate and fast algorithms for compensating phase and alignment errors. The paper proposes to use a Fully Connected Artificial Neural Network (FCANN) to correct the beam positioning perturbations by evaluating the beam shifts and tilts from two images taken at slightly different locations. Then, since it is practically impossible to have a large enough experimental dataset to train the neural network, this approach required developing an accurate and fast simulation method to evaluate the beam propagation in arbitrary directions, overcoming the limitations occurring when the computation must be repeated a large number of times. The numerical approach is a variant of the Angular Spectrum (AS) method, called Non Uniform ADaptive Angular Spectrum (NUADAS) method, which relies on the combination of non-uniform and adaptive Fourier transform algorithms to allow the computation of an arbitrary field distribution in a plane that is shifted and tilted with respect to the source. The parallel implementation of the NUADAS method is discussed and the numerical and experimental validations are presented. Then, an FCANN is trained using the synthetic dataset generated with the NUADAS method and the results are discussed, demonstrating the viability of the proposed approach not only for coherent beam combing, but also in other beam alignment applications.
Anna,Mauro; Valentina,Serafini; Chiara,Bellezza Prinsi; Matteo,Cavagnetto; Luca,Maggio Tanasi; Guido, Perrone
PHOTONICS - 2025
DOI / Linkabstract
Over the last decade, the number of demonstrations of Tm-doped fiber lasers has increased rapidly thanks to the applications of 2 μm fiber laser in sensing, surgery, and polymer processing. In the literature, there is plenty of evidence that increasing the output power and the efficiency of this class of fiber lasers is of interest to the scientific and industrial communities. This article presents a theoretical and experimental study on three possible pumping methods for a Tm-doped fiber laser: out-of-band pumping, using a semiconductor-based module emitting at 793 nm; in-band pumping, using an ad hoc homemade fiber laser emitting at 1600 nm; an intracavity configuration, in which in the pump light is generated within the laser cavity itself. This work demonstrates how applying alternative pumping methods does not lead to significant improvements in laser performance without first taking into account the losses introduced in the system when switching from a cladding-pumped to a core-pumped configuration.
Mauro, Anna; Bellone, Aurora; Olivero, Massimo; Vallan, Alberto; Perrone, Guido
PROCEEDINGS OF SPIE
DOI / Linkabstract
Establishing permanent bases on the Moon will require to develop wireless power transmission systems using high-power fiber lasers to support lunar missions where solar or nuclear energy is insufficient. Key challenges include minimizing weight, managing extreme temperatures, and mitigating ionizing radiation’s effects. This study investigates the sensitivity to X-rays of commercial rare-earth doped optical fibers for high-power lasers in accelerated tests. Different approaches are considered and compared, such as monitoring power degradation and fiber temperature changes, variation of the Rayleigh scattering signatures, and modifications of the spectral response of a fiber Bragg grating inscribed in a small section of the active fiber.
Serafini, Valentina; Pugliese, Diego; Bellone, Aurora; Perrone, Guido
PROCEEDINGS OF SPIE - 2023
DOI / Linkabstract
The paper presents the design and preliminary experimental validation of a fiber laser with direct emission in the yellow. The active material is a Dy-doped custom-made phosphate fiber, which is pumped by high-power blue diode lasers emitting at 450 nm. A suitable model has been developed to optimize the laser behavior and validated with a low-power version of the laser cavity with femtosecond written Bragg grating mirrors.
Bellezza Prinsi, Chiara; Bellone, Aurora; Cavagnetto, Matteo; Kulluri, Ritjola; Olivero, Massimo; Perrone, Guido
Optical Fibers and Sensors for Medical Diagnostics, Treatment, and Environmental Applications XXIV 2024
DOI / Linkabstract
The paper presents an all-optical system for the detection of bacterial contamination in flowing water that combines the readings from a multi-functional fiber Surface Plasmon Resonance (SPR) sensor with fluorescence measurements. The preliminary application to cases of water contaminated with Escherichia coli is discussed.
Bellone, Aurora; Olivero, Massimo; Vallan, Alberto; Perrone, Guido
PROGRESS IN BIOMEDICAL OPTICS AND IMAGING - 2025
DOI / Linkabstract
Endo-Venous Laser Ablation (EVLA) is emerging as one of most important minimally invasive procedures for treating varicose veins, offering reduced patient discomfort compared to traditional methods. The procedure uses a laser beam to collapse and induce sclerosis in vein walls, effectively sealing the vein. Among the various medical wavelengths, recent advancements favor the use of 1900nm lasers, particularly those based on thuliumdoped fiber technology, due to their highly localized heating effects. However, discrepancies in the literature regarding the optimal laser irradiation dose highlight the need for an applicator that integrates temperature sensors to provide the surgeon with real-time feedback. As a preliminary work the paper discusses the use of fiber Bragg gratings to measure the temperature distribution induced by two lasers emitting at the opposite edges of the commonly used therapeutic wavelength range. For easiness and better reproducibility the tests have been carried out on egg white phantoms, simulating vascular veins; the results demonstrate that heating at 1900nm outperforms that at 975nm by minimizing spurious temperature increases outside the target volume. Additionally, the experiments emphasize the importance of carefully tuning laser power to prevent carbonization. The outcomes of the ablation tests are in good agreement with those found in clinical trials, thus demonstrating promising capabilities of this novel applicator.