Keynote & Invited Speakers

Yasufumi Fujiwara      (Osaka University, Japan)

Title: “Semiconductors intra-center photonics”

Authors: Y. Fujiwara

Abstract: We have worked on the development of semiconductors intra-center photonics. This novel photonics uses the intra-4f shell transitions of rare-earth ions doped in semiconductors. In 2009, we invented a narrow-band red LED using Eu-doped GaN (GaN:Eu). The LED exhibits a main emission line at 621 nm with a full width of less than 1 nm, which can be assigned to the 5D0–7F2 transition of Eu3+ ions. The wavelength is extremely stable against ambient temperature and injected current. We have demonstrated monolithic integration of vertically stacked RGB LEDs composed of GaN:Eu and InGaN quantum wells on the same sapphire substrate. The emission color gamut of the integrated LED is extremely high compared with Rec.2020. The LED has a high potential as a key technology to realize a small, ultrahigh-definition micro-LED display applicable to smartphones/watches, vehicle displays, and wearable glasses for virtual reality and augmented reality.

Anna Luiza Lukowiak      (Institute of Low Temperature and Structure Research, PAS, Poland)

Title: “Novel photoactive biomaterials and biocomposites”

Authors: A. Lukowiak, W. Bodylska, K. Gluchowska, Y. Gerasymchuk, M. Fandzloch

Abstract: New materials and composites showing various activities after interaction with light are very promising in different areas of medicine. The proper composition makes them suitable for biological testing and optical properties broaden their range of applications. To show their utilization in photodynamic therapies, optical sensing, bioimaging, and antibacterial action, a few examples of optically active nanomaterials will be presented. In the case of bioactive glasses, photoactivity is ensured by modification of the glass composition by the addition of lanthanide ions or phthalocyanine complexes with metals (MePc). Graphite oxide (GO) decorated with MePc is effective in the generation of reactive oxygen species when the composites are exposed to red/near-infrared radiation. Properly designed metal–organic frameworks and their composites with hydroxyapatite can be useful for bioanalytic sensing. All materials have also antimicrobial properties desired in medicine.

Angela B. Seddon      (The Univ. of Nottingham, United Kingdom)

Title: “MID-IR photonics – A new frontier”

Authors: A. B. Seddon

Abstract: According to the International Organisation for Standardisation, the MIR wavelength region is 3-50 μm [1]. Molecular species emit or absorb mid-infrared energy when their vibrational state changes. Shining MIR light enables molecular detection and identification, for use here on Earth in environmental sensing, sensing for security, and in medicine and healthcare. Practical deployment of the MIR molecular detection requires the means to generate bright, MIR light across a broad spectrum and to route it to where it's needed. We are achieving this through the focused development of MIR fibre-optic devices/systems that are robust, functionally designed, safe, compact, and cost-effective. We are producing passive, and nonlinear, glass fibre to route, and emit, broadband MIR light, and luminescent fibre to pump this emission. MIR transparent chalcogenide glasses are exceptionally stable in water, liquid and vapour, and are not oxidised in an ambient atmosphere.

Simone Berneschi      (IFAC-CNR, Italy)

Title: “Fluorescence–based poct devices: strategies & perspectives in sepsis diagnosis”

Authors: S. Berneschi, C. Trono, S. Tombelli, A. Giannetti, B. Adinolfi, F. Chiavaioli, G. Persichetti, G. Testa, G. Quartu, G. Porro, R. Bernini, F. Baldini

Abstract: Sepsis, understood as a systemic pathology resulting from a worsening of a local infection state in human body, represents one of the main causes of mortality in patients recovered in intensive care and emergency units. A delay in the diagnosis and in starting an effective drug treatment turns out to be decisive both for promptly dealing with this pathology and for reducing the high hospital costs associated with it. Therefore, the advent of Point-Of-Care Testing (POCT) devices, capable of rapidly providing an early diagnosis of this disease by means of specific biomarkers detection close to the patient's bed, is highly desirable. The aim of this talk is to highlight the role played by dielectric-photonic (D-Photon) materials & devices in the development and performance of fluorescence-based optical POCT prototypes for sepsis, with particular reference to the research activity carried out by the authors in this area.

Stefano Bigotta      (Institut franco-allemand de recherches de Saint-Louis, France)

Title: “Latest advances in 2 µm single oscillator fiber laser sources”

Authors: S. Bigotta, A. Berrou, C. Clemente, N. Dalloz, T. Ibach, C. Louot,  A. Motard, F. Sanson, A. Hildenbrand-Dhollande

Abstract: Rare-earth doped fiber lasers emitting high optical powers in the 2 µm range are interesting laser sources because their emission wavelength is in the atmospheric transmission and eye-safe region. The compact and alignment-free systems that these high-power laser sources offer are ideal for civil and military applications such as gas detection, wind mapping, optical countermeasures and laser weapons, to name a few.

In this paper we report the latest advances in the development of high power 2 µm laser at the French German Research institute of Saint Louis. High power (~200 W) emission from single-oscillator monolithic singly Tm3+ and Tm3+-Ho3+ co-doped fiber is reported. The role of the dopant (Tm3+, Ho3+, or Tm3+-Ho3+co-doping) on the emitted wavelength and efficiency will be discussed.

Wilfried Blanc      (CNRS Université de Nice-Sophia Antipolis, France)

Title: “Why drawing conditions are important to tune the characteristics of nanoparticles in optical fibers?”

Authors: Z. Lu, M. Cabie, F. Pigeonneau, T. Neisius, D. Tosi, W. Blanc

Abstract: To develop new sensors and fiber lasers, nanoparticles-doped optical fibers are promising due to their ability to tune light scattering and luminescence properties. In this work, a fiber fabrication process is reported to tune the characteristics of oxyde nanoparticles inside the core. Several drawing parameters i.e., temperature, velocity and tension etc. are set to shift the particles behavior. A morphology study by SEM confirmed that with increasing drawing tension, more particles deformed along the longitudinal direction while a higher drawing temperature reduces the size of the nanoparticles. These results highlight the competition between two processes. One is governed by the thermodynamics leading to the dissolution of nanoparticles at high temperature. The second process, acting at lower temperature, is based on the Plateau Rayleigh capillary instability which plays a vital role in the elongation and breakup phenomena of nanoparticles. These results pave the way to customize nanoparticles in optical fibers.

Monica Bollani      (IFN-CNR, Italy)

Title: “ Flexible photonic platform based on dielectric antennas realized by solid state dewetting”

Authors: M. Bollani, N. Granchi, L. Fagiani, M. Modaresialam, M. Gherardi, A. Gatta Zini, B. Squeo, M. Pasini, A. Chiappini, F. Intonti, M. Abbarchi

Abstract: Flexible and stretchable photonics are emerging fields aiming to develop novel applications where the devices need to conform to uneven surfaces or whenever lightness and reduced thickness are major requirements. However, owing to the relatively small refractive index of transparent soft matter, these materials are not well adapted for light management at visible and near-infrared frequencies. Here we demonstrate simple, low cost and efficient protocols for fabricating Si1-xGex-based, sub-micrometric dielectric antennas with ensuing hybrid integration into different plastic supports. The dielectric antennas are realized exploiting the natural instability of thin solid films to form regular patterns of monocrystalline atomically smooth silicon and germanium nanostructures. Efficient protocols for encapsulating them into flexible and transparent, organic supports are investigated and validated. We benchmark the optical quality of the antennas with light scattering measurements, demonstrating the control of the islands structural colour and the onset of sharp Mie modes after encapsulation.

Alain Braud      (Université de Caen, France)

Title: “Fluoride crystals for high energy lasers applications”

Authors: A. Braud, C. Meroni, S.Montant, C.Maunier, P. Camy

Abstract: The doping of fluorite-type single crystals with Nd and multiple buffer ions reveals an unique possibility for broadband, high-energy, short-pulse laser amplification at 1µm, which makes these materials appealing to various high energy laser applications such as inertial confinement fusion (ICF). ICF requires high energy laser pulses with high repetition rates to boost the fusion efficiency. We have developed specific fluoride crystals with high thermal conductivity, and emission bands as wide as the Nd-doped glasses currently employed in laser amplification for ICF. These laser crystals comprise active Nd3+ ions with different buffer ions, namely Gd, La, Ce, Y, Lu, Sc and exhibit very good laser performance in cavity owing to their high optical quality along with a wide laser tunability. Amplification measurements using a dedicated tunable pump-probe setup allow a precise determination of their amplification characteristics confirming the attractiveness of these materials.

Giuseppe Brunetti      (Polytechnic University of Bari, Italy)

Title: “Multiplexed optical trapping trough dielectric metasurfaces”

Authors: G. Brunetti, C. Ciminelli

Abstract: Trapping devices use forces to accurately control and manipulate nano- or microobjects. Since Ashkin’s pioneering research, several optical trapping configurations have been developed, although devoted to trap individual or very few particles. On the other hand, biological studies typically require a large number of samples in order to provide meaningful statistics. In this framework, here, we present an innovative Si-based resonant metasurface able to trap a high number of nanoparticles (> 100) in parallel over tens of minutes, by exploiting the supported anapole state that generate a strong field enhancement.

Andrea Chiappini      (IFN-CNR Trento, Italy)

Title: “Nano and micro structured periodic materials as optical sensors”

Authors: A. Chiappini, A. Carpentiero, B. M. Squeo, A. Gatta Zini, L. Pasquardini, T. Virgili, M. Pasini, M. Bollani

Abstract: Recently, the great demand in terms of next generation photonic and electronic devices to be flexible, stretchable, reconfigurable, lightweight and portable, has driven significant research and industrial interest. In this frame, the realization of well-oriented photonic periodic structures is an important milestone in the development of photonic platforms operating in the visible range, with high flexibility and low fabrication cost. Here, we present our consolidated results concerning nano and micro structured periodic materials as optical sensors, focusing our attention on different chromatic structures that can find application in several fields thanks to complementary configurations: (a) composite systems based on colloidal crystals coupled/infiltrated with responsive materials, (b) metallic-dielectric structures and (c) buckling periodic elastic materials. We will describe how these systems can be used as suitable optical platforms in order to detect chemical and biological (bacteria) species.

Andrea Cusano      (University of Sannio, Italy)

Title: “Nanotechnology on Fibers: Towards Advanced Multifunctional Optrodes for Precision Medicine”

Authors: A. Cusano

Abstract: The panorama of urgent testing needs has driven the demand for Point-of-Care (POC) diagnostic systems enabling the sensitive detection of pathogens and biomarkers at extremely low concentrations and providing instant results under a cost-effective scheme.
Considering the technological maturity that has been achieved so far, at both fabrication and application levels, lab-on-fiber technology has the potential to significantly impact the technological roadmap towards advanced POC applications, though the development of the fundamental technological pillars at the basis of next-generation of POCs. The aim of this chapter is to present the current evolution and perspectives of lab-on-fiber optrodes towards advanced and multifunctional POC platforms. Optical fibers can be easily integrated in medical needles and catheters ensuring unprecedented miniaturization levels and multiplexing capabilities. The integration of judiciously designed functional nanomaterials features unprecedented light matter interaction levels opening new ways to detect biomolecules at unrivalled limits of detection.

Antonio D’Alessandro      (University of Rome La Sapienza, Italy)

Title: “Nanostructures for All-Optical Biophotonic and Microfluidic Devices for Photo-Thermal Applications”

Authors: C. Santini, F. Petronella, M. L. Sforza, L. De Sio, A. d’Alessandro

Abstract: In this work, we present and discuss a simple and effective design which combines optical and microfluidic channels to allow accurate investigation of gold nanorods (GNRs) potential in the development of light assisted antimicrobial therapies. The powerful combination allows the realization of innovative light-assisted antimicrobial treatments in a portable and biocompatible microsystem. In order to combine microfluidic channels and optical waveguides, we use PDMS as bulk substrate, since such elastomer has proved to be very effective and reliable for cheap soft lithographic fabrication of many microfluidic and microoptical devices.

Costantino De Angelis      (University of Brescia, Italy)

Title: “Analog image processing with nonlinear nonlocal flat-optics”

Authors: D. de Ceglia, A. Alù, D. Neshev, C. De Angelis

Abstract: We demonstrate that a seemingly simple system like a homogeneous dielectric sheet with second order nonlinearity can perform as an edge detector in real space. The advantages over edge-detection through linear flat optics include compactness, broadband operation, due to the non-resonant mechanism, very large contrast and better performance in the presence of noise. Beyond this example, the concept of combining nonlinear responses with engineered nonlocalities in metasurfaces offers a huge potential, leveraging the synthesis of amplitude, phase and angular dispersion of the tensor elements of nonlinear nonlocal metasurfaces. Our results indicate that Volterra kernels of nonlinear flat optics can open new low-hanging opportunities in applications such as image processing, item recognition for computer vision, high--contrast, and super--resolution microscopy, and unveil a new direction for the field of analog processing and computing through nonlocal nonlinear metasurfaces.

Francesco De Leonardis      (Polytechnic University of Bari, Italy)

Title: “Superlattice-on-Insulator Heterogeneous Integration Platform”

Authors: F. De Leonardis, and R. Soref

Abstract: It is recognized that heterogeneous integration of “different materials” is crucial to create a high-performance wafer-scale PIC on a large Si wafer. New platform development will play a key role in PICs as they grow in terms of functional complexity. The current trend is to move beyond SOI, and for that purpose the new SLOI (Superlattice on Insulator) platform is proposed, where SL consists of a low-loss waveguiding stack of N monolayers of material A (group III-V) and M monolayers of B (group IV or III-V) in each period. We have employed the semi-empirical tight-binding Hamiltonian in order to simulate the performances of the SLOI waveguides for both electro-optical and nonlinear cases. The work provides only theoretical guidelines on what SLOI performance can be expected. We calculate the metrics for SPDC and SFWM sources, Optical Parametric Oscillators, EO 1x1 modulation and EO 2x2 switching, demonstrating that SLOI is competitive with LNOI and BTOI and Polymer/SOI platforms.

Massimo De Vittorio      (University of Salento, Italy)

Title: “Interfacing the brain by photonic technologies”

Authors: M. De Vittorio, F. Pisanello

Abstract: In this talk, new technological and methodological approaches for interfacing the brain by photonic technologies will be shown. Tapered optical fibers are nanomachined and processed to produce optical probes and optrodes for accessing deep brain regions in animal models with spatial and temporal resolution. These minimally invasive probes can be simultaneously exploited in both optogenetics, for manipulation of neural activity, and for recording of molecular and cellular activity in fiber photometry. It will be also shown how tapered fibers can be employed in-vivo in Raman and SERS spectroscopy experiments for tumoral tissue identification and label-free neurotechnology.

Giovanni Del Greco      (Leonardo SpA, Italy)

Title: “Photonic Integrated Circuits for Multiband RF Transceiver in Arrayed Systems: The Picture Project”

Authors: G. Del Greco, P. Ghelfi, J. Bourderionnet, F. VanDijk, Y. Leguillon, L. Menager, L. Vivien

Abstract: The PICTURE project aims at investigating the potentials of integrated photonics for radar systems by targeting a photonics-based architecture for active electronically scanned array (AESA) antenna systems. The project targets the identification and development of specific devices and architectural solutions. Different technological platforms (Silicon on Insulator, Indium Phosphide, Silicon Nitride) are exploited to increase compactness and reliability.

Francesco Dell’Olio      (Polytechnic University of Bari, Italy)

Title: “All-dielectric metasurfaces supporting quasi-bound state in the continuum modes”

Authors: F. Dell’Olio

Abstract: A quickly rising research effort is currently focused on all-dielectric metasurfaces, which are an emerging flat-optics platform for sophisticated manipulation of electromagnetic wave propagation. Such metasurfaces can be properly engineered for supporting bound states in the continuum and have the potential to enhance the performance of a wide range of nanophotonic devices for lasing, sensing, and non-linear optics.
Recently, all-dielectric metasurfaces with squared and circular symmetry that support silicon-slot quasi-bound state in the continuum modes resonating in the near-infrared have been designed and experimentally demonstrated with measured Q-factor values close to 1,000.
In this presentation, I will give a critical overview of recent advances in the field, highlighting the underlying physical principles, describing some selected experimental evidence, and offering a look into future developments.

Dominik Dorosz      (AGH-University of Science and Technology, Poland)

Title: “Nanocomposite Ypo4:Yb3+ Doped Optical Fiber - Towards A New Class of Active Materials”

Authors: D. Dorosz, M. Kochanowicz, R. Valiente, A. Diego-Rucabado, N. Siñeriz-Niembro, M. Lesniak, J. Posseckardt, G. L. Jimenez, R. Müller, M. Lorenz, A. Schwuchow, M. Leich, K. Wondraczek, M. Jäger

Abstract: The glass powder doping method was used to produce the first glass-ceramic optical fibre doped with YPO4:Yb3+ active nanocrystals (ANCs). The advantage of this construction is the use of core glass with refractive index (n=1.78, λ=633nm) matched to the ANCs. It was obtained due to the separate preparation of ANCs and glass matrix. The YPO4:Yb3+ nanocrystals were synthesized by the solvothermal method and optimized for the size (~50 nm), shape, dispersion and Yb3+ concentration (3 mol.%) to obtain the required optical properties. Optical fibre was fabricated using powder-in-tube method, where the mixture of glass powder and ANCs (5% wt.) and Duran® glass tube were used as a core and cladding respectively. The presence of the crystals was confirmed by luminescence measurements and FIB/TEM-EDX analysis. Optical and luminescence properties of the nanocomposite optical fibre allow us to conclude that it may be a new class of active materials for lasing applications.

David González Ovejero      (Institut d’Électronique et des Technologies du numéRique, IETR - UMR CNRS, France)

Title: “Gradient and Modulated Metasurfaces for sub-THz Arrays and Beam-Formers”

Authors: D. González Ovejero, C. Bilitos, J. Taillieu

Abstract: Sub-terahertz (sub-THz) frequency bands will allow one to benefit from large unlicensed bandwidths and thus satisfy the need for higher data rates. However, to make the most of such large bandwidths, one has to compensate the free space path loss, which is proportional to the carrier’s frequency and typically burdens the link budget for sub-THz bands. Moreover, the generation of power at room temperature in the sub-THz gap is also challenging. Therefore, high-gain antennas radiating narrow pencil beams must be adopted. Typical architectures consist of scalar horns used as focal source for large reflector and lens systems. Although efficient and wideband, such architectures are bulky and difficult to adopt in a paradigm that foresees the massive deployment of small cells. As opposed to electrically large reflectors and lenses, we will discuss the use of gradient and modulated metasurfaces as low-profile and light-weight architectures that can provide similar gains without imposing a toll on the relative bandwidth.

Christopher Holmes      (University of Southampton, United Kingdom)

Title: “Flexible Glass Photonics and Applications for Aerospace”

Authors: C. Holmes, S. Zahertar, B. Moog, M. Godfrey, T. Lee, A. Annunziato, F. Anelli, B. Shi, M. Beresna, M. Whitaker, F. Prudenzano, R. Day, J. Dulieu-Barton

Abstract: Flexible photonics have enabled innovative devices to be conceived, including new sensing possibilities offered by removing of a rigid substrate. This captures specific work at the University of Southampton, were planar silica-based flexible photonics fabricated through both wafer scale flame hydrolysis deposition and optical fibre drawing of a planar glass substrate (flat fibre) have mapped against needs of the aerospace sector. Developments demonstrated include enhanced sensing in high value carbon fibre composite airframes, new branching network topologies inside glass fibre composite and high fidelity, lightweight Bragg grating interrogators. Through these developments advances are now beginning realised including feedback control during manufacturing of composite material and digital twin synthesis of aerial drone platforms.

Tindaro Ioppolo      (New York Institute of Technology)

Title: “Optical Micro-Sensors Based on Dielectric Resonator”

Authors: T. Ioppolo

Abstract: The performance of micro-photonic sensors based on dielectric cavities will be presented. The sensing approach is based on the whispering gallery mode (WGM) of micro-optical resonators. In optics, the whispering gallery mode phenomenon (WGM) arise from total internal reflection of light at the internal surface of a high index of refraction dielectric resonator embedded in a surrounding medium of lower refractive index. Perturbation of the resonator morphology induced by an external effect induce a shift in the WGM. Thus, the external effect inducing the perturbation is measured by tracking the WGM shift. Tethered and untethered sensors will be presented. Tethered sensors are coupled to an optical fiber that serves as input output to excite and interrogate the optical modes. Untethered sensors are microscale lasers that are excited using a light source and the optical modes are interrogated using a spectrometer. This last configuration allows for remote sensing.

Bernhard Lendl      (Technical University of Wien, Austria)

Title: “Advancing mid-IR evanescent wave based sensing strategies for the analysis of proteins in water”

Authors: B. Lendl, S. Vijayakumar, M. David, B. Hinkov, B. Schwarz, G. Strasser

Abstract: Accurate analysis of proteins is of high relevance in many fields, including bio-process monitoring, characterization of bio-pharma formulations or in milk analysis to name just a few. As the activity of proteins is linked to their secondary structures, mid-IR spectroscopy is a valuable method in this realm because conformational changes of proteins are encoded in the position and shape of their amide I absorption bands (~1600 to 1700 cm-1).

This presentation will present recent advances in the field of integrated photonic devices for achieving highly sensitive protein detection. We report on evanescent wave sensing using Ge on SOI of liquid samples, as well as using planar, dielectric loaded gold plasmonic waveguide structures. Furthermore, the concept of a lab-on-a-chip-system comprising quantum cascade lasers as well as quantum cascade detectors and plasmonic waveguides will be introduced on the example of in-situ protein spectroscopy in heavy water.

Giansergio Menduni      (Polytechinc University of Bari, Italy)

Title: “Quartz Tuning Fork as Infrared Photodetector in Tunable Diode Laser Absorption Spectroscopy”

Authors: G. Menduni, A. Zifarelli, S. Dello Russo, T. Wei, M. Giglio, P. Patimisco, A. Sampaolo, H. Wu, L. Dong, V. Spagnolo

Abstract: In the past decade, the rapid development of infrared laser technology has led to an increasing demand for photodetectors with high sensitivity and a wide operative spectral range suitable for spectroscopic applications. In this work, we report on the study of light-induced thermoelastic effects occurring in quartz tuning forks (QTFs) when exploited as light detectors in Tunable Diode Laser Absorption Spectroscopy (TDLAS) sensors. The induced photothermal processes and the temperature distribution following the absorption of laser beam upon the crystal quartz was studied by using finite-element-analysis. The electromagnetic energy release and the induced thermal distribution were related to the absorbance curve of the quartz crystal. In the spectral region with high absorption, the radiation travels few tens of micrometers in the quartz crystal, while in the spectral region with low absorption, the radiation is trapped at the interface between the chromium film and the highly reflective gold layer.

Luca Poletto      (IFN-CNR, Italy)

Title: “Laser diodes for Raman analysis of gas mixtures: applications to energy and agrifood”

Authors: L. Poletto

Abstract: Recent applications of Raman analysis on gases will be discussed, with applications to energy and agrifood. Raman spectroscopy is a non-invasive, full-optical and fast technique to measure the composition of gaseous mixtures, including species, such as nitrogen and hydrogen, that cannot be measured with conventional optical absorption techniques. Raman has been applied for the analysis of combustion gases in order to measure the calorific value in a compact setup. Tests on certified mixtures show that the calorific value can be measured with an uncertainty of ±0.1% and a precision of ±0.5% on natural gas mixtures, including hydrogen-enriched mixtures. In the agrifood sector, Raman has been used to measure the bacterial contamination on milk samples, in order to distinguish between bacteria producing carbon dioxide (cereus) from those producing also hydrogen (clostridia). The Raman analysis, in this case, has been performed on vials containing the possible contaminated sample and measuring the gas mixture in the head space.

Pier Sazio      (University of Southampton, United Kingdom)

Title: “Fibre photonics functionalised with semiconductors, metals, 2D materials and catalysts”

Authors: P. Sazio, F. De Lucia, A. Lewis, W. Belardi, M. Potter, D. Stewart, R. Raja, D. Hewak, and J. Baddin

Abstract: Developed over two decades, the high-pressure technique invented by our groups at Penn State and ORC Southampton, have been used to fill the large number of micro- and nanoscale pores in microstructured optical fibres, including the latest generation of Hollow-core Antiresonant (ARF) fibre to create a novel class of Composite Material ARF (CM-ARF) waveguide, thus providing flexibility to enhance the potential application base of these devices. We have integrated bulk semiconductors such silicon and more recently, 2D TMDC materials such as MoS2 inside CM-ARFs. Finally, we present very recent work on the incorporation of catalytic materials inside microstructured optical fibre canes, thus combining for the first time, microstructured optical fiber technology with photocatalysis, creating a microreactor for water splitting and hydrogen generation. In doing so, we create a system capable of effectively combining photons, liquids, and gases within a monolithic, highly confined, transparent silica geometry.

Gaetano Scamarcio      (University of Bari, Italy)

Title: “Graphene Terahertz Modulators”

Authors: G. Scamarcio, S. M. A. Sarfraz, A. Di Gaspare, E. A. A. Pogna, E. Riccardi, C. Di Franco, M. S. Vitiello

Abstract: Graphene posseses unique optical and electrical properties that can enable manipulation, propagation and detection of electromagnetic waves over a broad spectral range, with a high level of control, offering the potential to activate different functionalities, by optical or electrical means, in a single chip. Its electrostatically tunable optical conductivity, band structure and transport characteristics, and the possibility to be integrated into hybrid optical devices at the nanoscale, offer valuable opprtunities for engineering amplitude modulators, spatial light modulators and switches, combining high efficiency intensity modulation, and spectral tunability in the underexploited high (1.5 – 5 THz) terahertz frequency range.

Here, we review our recent results on graphene-based terahertz modulators exploiting quarter wavelength optical cavities and either electrolyte-gated super-capacitor or grating-gated structures . We demonstrate highly efficient amplitude modulation (> 40 %), frequency tuning in the 2-5 THz range, saturable absorption mirror operation and fine-tuning capability of quantum cascade laser combs. We also demonstrated modulator arrays with no cross-talk. These results open intriguing perspectives for applications of THz optical systems.

Vincenzo Schena      (Thales Alenia Space Italia, Italy)

Title: “Internet Through The Space: The New Way To Conceive And Extend The Connectivity At Thales Alenia Space”

Authors: V. Schena, G. Rinelli, S. Di Bartolo, L. Rodio

Abstract: The space is experiencing an epochal renewal that is leading it to rapidly change its paradigm of "niche" technology to become something much closer to the common sense of consumer-type products and services as is already the case today for mobile telephony, the access to the Internet and so on.

The increasingly affirmation of the 5G Non Terrestrial Network (NTN) protocol and, subsequently, the 6G is offering the opportunity in the immediate future to have an integrated space-terrestrial network capable of extending connectivity on the entire globe. 

This will drastically and effectively reduce the Digital Divide everywhere, introducing new services useful for improving both European and global society.

Luigi Sirleto      (IMM-CNR, Italy)

Title: “Noises investigations in femtosecond stimulated Raman scattering microscopy”

Authors: R. Ranjan, G. Costa, M. A. Ferrara, M. Sansone, L. Sirleto

Abstract: Label-free stimulated Raman scattering microscopy allows the image of a variety of molecular species, targeting their intrinsic chemical bonds in the C-H region (>2800 cm-1), the silent region (1800-2800 cm-1), and the fingerprint region (<1800 cm-1). In this talk, hardware characterization by systematic measurements of noise sources is described, demonstrating that our in-house built microscope is shot noise limited. Secondly, the statistical properties of the overall image noise are analyzed, and we prove that the noise distribution can be dependent on image direction, whose origin is the use of a lock-in time constant longer than pixel dwell time. Finally, we compare the performances of two widespread general algorithms, i.e. Singular Value Decomposition (SVD) and Discrete Wavelet Transform (DWT), with a method, i.e. Singular Spectrum Analysis (SSA), which has been adapted for SRS images. In order to validate our algorithms, in our investigations lipids droplets (LDs) have been used and we demonstrate that the adapted SSA method provides an improvement in image denoising.

Silvia Soria      (IFAC-CNR, Italy)

Title: “Chaotic Oscillations in PhoXonic Cavities”

Authors: G. Frigenti, D. Farnesi, S. Pelli, G. Nunzi Conti, S. Soria

Abstract: We report on the experimental and theoretical analysis of parametrical optomechanical oscillations in microbubble whispering gallery mode resonators due to radiation pressure. MBR are efficient phoxonic cavities that can sustain both optical photons and acoustic phonons. The optically excited acoustic eigenmodes of the MBR oscillate regeneratively leading to parametric oscillation instabilities. The studied regimes include the enhancement of the oscillations, the suppression of nonlinear phenomena, and their transition to chaos following two different routes: quasi periodic doubling bifurcation and a set of discrete lines into a continuum, and finally a continuum or directly into a continuum. We have also studied the temporal behavior of the cavity, the coexistence and the suppression of the oscillation while generating Turing comb patterns. When the suppression occurs, we generate photons in other resonant modes equally spaced. We also report the chaos transfer from a strong pump to a very weak probe in microbubble resonators.

Patty Stabile      (Eindhoven University of Technology, Netherland)

Title: “InP Photonic Integrated Neural Networks”

Authors: B. Shi, N. Calabretta, R. Stabile

Abstract: Neuromorphic photonics is an emerging research field that develops an alternative approach to electronics with the attempt to set a milestone in increasing computing speed and energy efficiency. We map artificial neural models on chip to realize photonic integrated neural networks, using a combination of Semiconductor Optical Amplifiers (SOAs) and Array Waveguide Gratings (AWGs). The use of Wavelength Division Multiplexed (WDM) input signals, all-optical monolithically integrated neurons and a multi-layer networks are demonstrated, opening to all-optical neural networks. Scalability studies are performed and arbitrarily deep photonic neural networks are demonstrated to be feasible, without impacting final accuracy. Massive parallelism is introduced via the combination of space and wavelength domains, to further accelerate WDM based convolutional neural networks on chip. Finally, a new concept for a 3D neuron and neural network is introduced, together with predicted performance, opening to a promising and feasible technology for peta-scale neuromorphic photonics.

Marinella Striccoli      (IPCF-CNR, Italy)

Title: “Carbon Dots: New Fluorescent Nanoparticles for Advanced Optical Applications”

Authors: G. Minervini, A. Madonia, M.L. Curri, E. Fanizza, A. Panniello, M. Striccoli

Abstract: Carbon dots (CDs) are novel fluorescent nanoparticles that combine intense emission of visible light with eco-friendly and inexpensive carbon-based composition. While carbon is generally regarded as an optically black material, CDs possess surprising light emitting capabilities; their intense absorption bands can be photoexcited to express a bright fluorescence occurring in the whole range of the visible spectrum, often associated to high quantum yields. Being composed of elements such as carbon, oxygen, hydrogen, and nitrogen, CDs are regarded as inexpensive and biocompatible nanoparticles. Here, the synthesis and the main optical properties of this extraordinary organic nanostructured fluorophores will be illustrated, in the perspective of their application in appealing nanocomposites for color converting white emitting devices. Furthermore, highly luminescent nanoparticles can be produced starting from organic dyes, showing improved resistance to photobleaching under UV excitation and emission from solid-state. Finally, dye-based CDs demonstrated efficient and stable lasing emission, thanks to the protective effect of the carbonaceous matrix.

Sławomir Sujecki      (Wroclaw University of Science and Technology, Poland)

Title: “Experimental Study of Mid-Infrared Q-Switched Pulses Emitted by Dy3+ Doped Fiber Laser”

Authors: S. Sujecki, Ł. Sójka, Ł. Pajewski, S. Phang, M. Farries, D. Furniss, E. Barney, T. Benson, A. Seddon, S. Lamrini

Abstract: An experimental analysis is given of a lasing action in fluoride glass fiber lasers that operate within a pulsed regime induced by a Q-switch modulator placed within the laser cavity. Particularly the aim of the study focuses on the determination of the pulse length and peak power that can be achieved by modifying the fiber length, repetition rate and pump power. The considered transition allows for addressing the wavelength range stretching from 2900 nm to 3400 nm. The observed lasers pulse peak power is on the level of 70 Watts while the laser pulse duration is less than 150 ns. Laser repetition frequency varied from 1 kHz to 10 kHz, which is significantly larger than this usually observed in the case of erbium doped fluoride glass fiber lasers. The considered pumping system is based on easily commercially available ytterbium fiber laser operating at 1100 nm.

Johann Troles      (University of Rennes1, France)

Title: “Mid-infrared fibers made by additive manufacturing of chalcogenide glasses”

Authors: J. Troles, L. Szymczyk, F. Cheviré, R. Lebullenger, A. Gautier, L. Calvez, C. Boussard, F. Charpentier, H. Tariel, Y. Guimond, M. Roze, G. Renversez

Abstract: In recent years, a growing interest has settled for optical materials and fibers for the mid infrared (mid-IR) region. This interest originates from societal needs for health and environment for instance, and also from demand for defence applications.

In this context, we have investigated an alternative way for Mid-IR fabricating, optical components such as preforms, optical fibers, sensors and lenses by using an original 3D printing process. In our work, the 3D-printing set-up has been specially designed for soft glasses. By using this additive manufacturing method, preforms with complex designs can be fabricated in a single step within a couple of hours, with a high degree of repeatability and of precision of the geometry. This original 3D printing method, open the way to many applications involving chalcogenide fibers manufacturing but also many other chalcogenide glass optical devices.

William Whelan-Curtin      (Munster Technological University, Ireland)

Title: “PhC cavities for CMOS on chip integration”

Authors: S. Iadanza, G. C. R. Devarapu, A. Blake, P. Acosta Alba, J. M. Pedini and L. O’Faolain

Abstract: We will present an on chip photonic integration solution that is compatible with Front End of Line integration process using deposited polycrystalline silicon (poly:Si) for on-chip optical interconnect applications. We used deposited silicon integration on a bulk silicon wafer to realise silicon high Q Photonic Crystal PhC) resonators, demonstrating the possibility to employ optical resonators realised in this material for the next generation of 2D and 3D integrated optical interconnects.