Conference Agenda

The integration of large-area and transparent all-dielectric metasurfaces capable of sustaining photonic bound states in the continuum (BICs) with biomolecular recognition elements such as aptamers and molecularly imprinted polymers (MIPs) presents a promising avenue for achieving ultrahigh sensitivity in biosensing applications. BICs, distinguished by their infinitely high Q-factors and non-radiative nature, offer exceptional opportunities for enhancing light-matter interactions, thereby enabling unparalleled sensitivity to minute variations in refractive index. By leveraging the unique properties of BICs within photonic crystal slabs and coupling them with selective recognition elements, we aim to develop highly selective and sensitive biosensing platforms capable of detecting these analytes at trace levels, even at pico- and femtomolar concentrations. Here we present recent results regarding BIC-based biosensors in detecting and quantifying various biomolecules, including proteins and toxins in food. Furthermore, we present a novel sensor platform that enhances the BIC sensing principle with a MIP cladding layer tailored for specific binding to transforming growth factor-beta (TGF-β), a pivotal cytokine involved in diverse cellular processes. These advancements represent a significant stride in biosensing technology, offering versatile and efficient platforms with broad applications across scientific, industrial, and societal domains.

Achieving a robust chiral response in plasmonic metasurfaces is among key goals of current nanophotonic research. In this work, we theoretically show that the circular dichroism (CD) of a metal metasurface can be maximized by exploiting the concept of a bound state in a continuum (BIC) together with symmetry breaking. We consider a gold metasurface with a deformation of circular holes into oval holes. The chiral response at small values of the angle of incidence is dominated by a quasi-BIC, with nearly maximal values of the absorption CD that are almost independent of the deformation. Strong emission CD is also demonstrated. Symmetry analysis and mode profiles show that the extrinsically chiral response does indeed follow from a symmetry-broken BIC, and is associated with a strong enhancement of the local electrical field. The concept of a plasmonic BIC with symmetry breaking provides a robust pathway to increase the chiral response in metal metasurfaces and opens research opportunities in chiral plasmonics that combine narrow resonances with local field enhancement.

While the classical concept of phase of a coherent oscillation is a well defined notion, many attempts to describe its quantum mechanical counterpart failed. Here, we show a nouvel formulation of the quantum phase operator, which encompass previous problems and can be applied to any oscillatory system, as mechanical oscillator or electromagnetic field. Our formulation starts from a two-dimensional harmonic oscillator, and uses development by Newton’s binomial identity to action of the operator on any Foch state or linear combination of Foch states. We also introduce a physical interpretation of non-integer state number of the harmonic oscillator, overcoming a major limitation for the interpretation of the previous suggested forms of the phase operator. Applications of this novel approach to monomode displaced gaussian beam and doubled displaced states are also shown. Our formulation of the quantum phase operator bypasses the requirement of P, Q, or Wigner representation in the phase space and can be directly applied to Fock states. This approach offers a convenient mathematical framework for manipulating and analyzing phase properties in uantum systems.

On the tenth anniversary of the first demonstration of daytime radiative cooling, we will both provide an introduction to, and survey, the state of the field, highlighting the role of advanced in optical and nanoscale materials in enabling recent progress. We will also look ahead to new frontiers and challenges in radiative cooling materials and technological applications enabled by radiative cooling.

Self-adaptive thermoregulation, the mechanism living organisms use to balance their temperature, holds great promise for decarbonizing cooling and heating processes. This functionality can be effectively emulated by engineering the thermal emissivity of materials to adapt to background temperature variations. Yet, solutions that marry large emissivity switching (Δϵ) with scalability, cost-effectiveness and design freedom are still lacking. Here, we fill this gap by introducing infrared dipole antennas made of tuneable thermochromic materials. We demonstrate that non-spherical antennas (e.g. nanorods) made of vanadium-dioxide can exhibit a massive (~200-fold) increase in their absorption cross-section as temperature rises. Embedding these antennas in polymer films, or simply spraying them directly, creates free-form thermoregulation composites, featuring an outstanding Δϵ~0.6 in spectral ranges that can be tuned at will. Our research paves the way for versatile self-adaptive heat management solutions (coatings, fibers, membranes, and films) that could find application in radiative-cooling, heat-sensing, thermal-camouflage, and other.

Radiative cooling involves decreasing the temperature of a body by emitting infrared radiation. When the heat loss from the emitting surface exceeds the heat gain, e.g., from the sun or the atmosphere, a passive net cooling effect occurs without the need for electricity or other power sources. Integrating radiative cooling materials with other renewable energy technologies represents a promising frontier in sustainable energy systems. In this study, we explore the strategic utilization of the net cooling effect resulting from radiative cooling materials to enhance the efficiency of photovoltaic panels, as they are susceptible to performance degradation with temperature variations. Our investigation focuses on the integration of these materials with photovoltaic cells and explores the possibility of integrating them in to other renewable energy technologies such as thermoelectric generators, addressing critical challenges, including thermal management, efficiency optimization and operational stability.

We present preliminary results on the fabrication of patterned surfaces by Direct Laser Interference Patterning and the characterization and theoretical interpretation of their infrared emissivities. The upgraded experimental method is capable of studying the full directional emission of samples under a controlled atmosphere at high temperatures. The effects of surface patterning can be quantitatively studied and modeled using a numerical method based on rigorous coupled-wave analysis (RCWA), a technique usually employed for periodic surfaces. The results show that laser interference patterning is capable of modifying the infrared emission of metallic materials, and that these changes can be accurately measured and numerically reproduced.

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Photonics21 is democratic, industry driven, stakeholder organisation following a people-parliament-government principle, representing over 4,000 personal members from all over Europe.

Photonics21’s main objectives are:

• Empower open strategic autonomy and a resilient, green, digital economy for Europe – creating roadmaps for European photonics and its value chains.

• Strategic collaboration with other initiatives – photonics enabling the technologies in all key parts of current and future supply chains.

• Empower regional, national and European public investment in photonics.

• Improve financing opportunities for photonics start-ups and SMEs.

• Engage the community and promote photonics as a key enabling technology for Europe.

PhotonHub Europe has been established to accelerate the uptake, integration, and deployment of photonic technologies in innovative products across a range of industry sectors for scaled-up business growth and production in Europe. The aim is to lower the innovation barriers for European industry by offering a one-stop-shop solution for exploiting the power of photonics in new “photonics-enabled” products and production methods. PhotonHub has received funding from the European Union’s Horizon 2020 research and innovation program under the Grant Agreement n°101016665, in Public Private Partnership with Photonics21.

The field of photonics needs more well-prepared professionals to support its growth and innovation potential. Addressing this pressing necessity requires engaging all stakeholders to increase the visibility of the outstanding professional opportunities available in photonics in academia, industry and beyond, and provide the future workforce with tools to boost their employability. In this session we want to talk about how the EU projects Carla and it's follow up project 360 CARLA are approaching this through innovative inclusive career development events and round up programs general to photonics or focused on photonics applications verticals.

Hyperspectral imaging (HSI) is a very powerful tool to study artworks in a non-contact way. Nevertheless, typical HSI systems, which rely on spatial-scanning and dispersive spectrometers, suffer from high-light losses and are difficult to operate for analysing complex artworks. Here we review the capabilities of a HSI system based on TWINS, an innovative Fourier Tranform (FT) spectrometer, which allows wide-field imaging. We demonstrate how, by coupling the TWINS to different imaging systems, it is possible to achieve multi-scalar configurations from very large field-of-view (FOV) acquisition to microscopy. Further, we show how the high-collection throughput of the device allows for the sequential and fast detection of multi-modal signals’, as diffuse reflectance, transmittance, photoluminescence (PL) and Raman.

The characterization of deterioration processes in wooden artifacts is crucial for assessing their state of conservation and ensuring their preservation. Advanced imaging techniques are currently being explored to study the effect of chemical changes on the structural and mechanical properties of wood. Combined second harmonic generation and two-photon excited fluorescence (SHG/TPEF) imaging is a recently introduced non-destructive method for the analysis of cellulose-based samples. The study of age-related wood degradation based on nonlinear signal variation is a promising avenue. This work involves nonlinear multimodal analysis of naturally aged and dendrochronologically dated spruce samples. SHG/TPEF imaging and fluorescence lifetime imaging microscopy (FLIM) were used to demonstrate the influence of molecular deterioration and rearrangement of biopolymers on the fluorescence emitted by lignin and the second harmonic signal generated by cellulose. Imaging based on spectral filter detection and time-resolved analysis of the nonlinear fluorescence signal was used to delineate and potentially quantify ageing-induced morpho-chemical changes in the ultrastructure of wood cells. The analysis of cell structures by optical sectioning revealed variations between wood samples of different ages and different cell structures.

This work introduces a novel method to multivariate analysis applied to fused hyperspectral datasets in the field of Cultural Heritage (CH). Hyperspectral Imaging is a well-established approach for the non-invasive examination of artworks, offering insights into their composition and conservation status. In CH field, a combination of hyperspectral techniques is usually employed to reach a comprehensive understanding of the artwork. To deal with hyperspectral data, multivariate statistical methods are essential due to the complexity of the data. The process involves factorizing the data matrix to highlight components and reduce dimensionality, with techniques such as Non-negative Matrix Factorization (NMF) gaining prominence. To maximize the synergies between multimodal datasets, the fusion of hyperspectral datasets can be coupled with multivariate analysis, with potential applications in CH. In this work, I will show examples of this approach with different combinations of datasets, including reflectance and transmittance spectral imaging, Fluorescence Lifetime Imaging and Time-Gated Hyperspectral Imaging, and Raman and fluorescence spectroscopy micro-mapping.

The discovery of the Herculaneum papyri in the 18th century at the Villa dei Papiri has captivated scholars due to their preservation from the 79 A.D. eruption of Vesuvius and their rich historical content. These papyri, containing knowledge from Greek philosophical schools, present significant challenges for readability and interpretation due to their carbonized condition. The ERC Advanced Grant “GreekSchools” project aims to develop new protocols using optical methods to enhance text analysis, facilitating a new critical edition of Philodemus’ "Arrangement of the Philosophers." To uncover hidden texts and locate overlapping layers, we employ advanced non-invasive techniques across various spectral regions, including Macro X-Ray Fluorescence Imaging (MA-XRF), Shortwave-Infrared Hyperspectral Imaging (SWIR HSI), technical photography in the visible (VIS), ultraviolet (UV), and infrared (IR) regions and high-resolution digital microscopy in the VIS and NIR. This contribution compares various acquisition methods and image processing techniques in the NIR and SWIR regions to enhance the visualization of the writing patterns.

Throughout the 20th Century, plastics found extensive use in fashion, art, and design due to their versatile nature. However, their degradation over time poses challenges, impacting material integrity, particularly in museum collections. To tackle this issue, different scientific techniques have been employed to study polymers. In this work, a complementary multi-analytical approach is proposed to investigate the light stability of ABS compounds, selecting LEGO® bricks as reference material. The method is based on fluorescence emission and lifetime integrating point-like analysis and imaging systems to corroborate chemical and spatial information specifically addressed at the surface level. The latter has shown promising results in studying ABS objects, offering insights into degradation and aiding conservation efforts.

Dual and multi-wavelength digital holography has demonstrated to be a relevant tool for desensitized testing of optical surfaces, large deformation of structures or surface shape profiling. With the advent of digital holography, a wide range of applications of dual/multi-wavelength holography was demonstrated, such as endoscopic imaging, calibration of mechanical structures, erosion measurements, in-line industrial inspection, melt-pool monitoring in additive laser welding manufacturing or more recently accurate profiling by coherence scanning profilometry.

However, due to the natural roughness of the inspected surface, speckle decorrelation occurs and noise is included in the data. This noise refers as the “speckle decorrelation” noise. Especially, the noise is non Gaussian, non-stationary, amplitude–dependent and may be anisotropic. In order to yield high quality data for metrology purpose, speckle decorrelation is required to be reduced. Recently deep leaning has emerged as a powerful and rapid approach for processing phase data. This paper proposes an overview of dual and multi-wavelength digital holography approaches and aims at describing the last theoretical results in the analysis of the standard deviation of decorrelation noise. The influence of noise in the measurements of the surface shape is described by an analytical approach. Numerical simulations with realistic experimental parameters are provided and discussed.

Gold standard imaging modalities in biological field are based on fluorescence signals providing high specificity and high resolution. Recently, Fluorescence Microscopy has been combined with microfluidics to develop instrumentations called Imaging Flow Cytometers, high-throughput tools that supply bright-field, darkfield and multiple-channels fluorescence images of each single cell passing in the Field Of View (FOV). Nevertheless, Fluorescence Microscopy has some drawbacks as phototoxicity, photobleaching, expensive costs for sample preparations and also the a-priori knowledge of the tags to be used. For these reasons label-free imaging methods greatly increase in the recent years as the Quantitative Phase Imaging (QPI) technologies for microscopy. One of the optical techniques to achieve QPI is Digital Holography. DH in microscopy has several advantages such as the possibility to numerically scan the focal distance, a properties that open to the integration of DH in microfluidics. Indeed DH combined with microfluidic circuits allows to image particles or cells flowing into the FOV at different depths. Here the capabilities of label-free single-cell imaging by DH are presented and their implications on next future biomedical applications discussed. Static or in-flow configurations combined with DH will be showed describing recent results and perspectives also in combination with Artificial Intelligence architectures.

Traditional methods used to realize the primary standard for the absolute optical power standard rely on expensive equipment and require well-trained personnel for maintenance and measurement activities. Silicon photonics technologies have enabled the development of predictable photodiodes with uncertainty comparable to (or perhaps better than) traditional methods. This work will report these research activities.

More than forty years ago, in 1982, we proposed the concept of quantum dot lasers and at the same time theoretically predicted the temperature insensitivity of the threshold current. With advances in growth technology, the predicted characteristics were demonstrated in 2004, and high-temperature operation up to 220°C became possible in 2011. Currently, quantum dot lasers are positioned as a promising light source for silicon photonics, especially in terms of their ability to operate at high temperatures in co-packaged optical technology. In this talk, I will describe the historical development of quantum dot lasers and their integration into 5 mm square silicon-based transceiver chips, as well as the direct epitaxial growth of quantum lasers on silicon. The talk will also demonstrate the integration of quantum dot-based light sources, including single-photon sources, on silicon integrated circuits using transfer printing methods.

All-optical wavelength converters and frequency synthesizers represent essential components for the development of advanced and reconfigurable optical communications systems. In this respect, the exploitation of intermodal nonlinear processes in integrated multimode waveguides has received significant attention in recent years for all-optical processing applications. Here, we discuss our recent results on the realization of fully-integrated and broadband wavelength converters utilizing the Bragg scattering intermodal four-wave mixing nonlinear process in a silicon-rich silicon nitride platform.

The structural and optical properties of p-doped Ge quantum wells separated by SiGe barriers are presented. The composition profile was determined by atom probe tomography and X-ray diffraction measurements. The energy and broadening of the fundamental intersubband transition were studied by Fourier transform infrared spectroscopy which revealed a strong absorption peak around 8.5 μm making this or similar heterostructures suitable for the realization of optoelectronic devices working in the fingerprint region.

We employ an ab initio Maxwellian approach using quasinormal-mode theory to derive an "exact" Maxwell evolution (EME) equation for resonator dynamics. The new differential equation bears resemblance to the classical one found in coupled-mode-theory (CMT); however, it introduces novel terms embodying distinct physics, suggesting that the CMT predictions could be faulted by dedicated experiments. The new equation is anticipated to be applicable to all electromagnetic resonator geometries, and the theoretical approach we have taken can be extended to other wave physics.

Stimulated Raman scattering in transparent glass-ceramics (TGCs) based on bulk nucleating phase Ba2NaNb5O15 were investigated with the aim to explore the influence of micro- and nanoscale structural transformations on Raman gain. TGCs are composed of nanocrystals that are 10–15 nm in size, uniformly distributed in the residual glass matrix. A significant Raman gain improvement for both BaNaNS glass and TGCs with respect to SiO2 glass is demonstrated, which can be clearly related to the nanostructuring process.

We study coherent perfect absorption in organic microcavity resonators and extend these principles

and our findings to more complex microresonator systems that, beyond absorption, also possess additional cavity energy dissipation mechanisms. The experimental approach uses laser interferometry to closely monitor the energy fluxes within the system at all device ports as a function of the device geometry and the phase relationships of the incident beams. A particular focus is on optical systems based on 2nd order Bragg gratings, which are crucial for the operation of organic distributed feedback (DFB) lasers or as light incouplers in optical waveguiding films. Coherent control allows the diffraction efficiency of the underlying grating to be tuned over a wide range of values. This strategy allows significant optimisation of resonator structures for high efficiency light coupling in optical waveguides and fine tuning of grating parameters for the most efficient optical mode conversion.

With the development of compact optical devices, there is an increasing demand for the integrated photonic platform. Here, we fabricated planar resonant cavities for surface waves on one-dimensional photonic crystals, based on reverse design. The cavity is coupled to a linear waveguide. Experimental data proved the injection of Bloch Surface Wave (BSW) into the waveguide with a narrow bandwidth. Our work offers a platform to facilitate integration of single photon sources on BSW-based chips.

Chirality is characterized by the absence of mirror symmetry , it’s an intrinsic property of certain entities in the universe and influences molecular interactions and properties. Measure circular dichroism (CD) using a circular polarized light is a standard technique but its sensitivity is often limited. In this work , we explore extrinsic chirality, a property arising from asymmetric achiral materials , using a photo-acoustic spectroscopy. Photo-acoustic spectroscopy allows direct measurement of local absorption, by monitoring the heat produced and transferred to the surrounding air, regardless the transmitted, reflected, and scattered light that flows away from the sample. In conventional techniques, the CD is usually measured by taking into account only the extinction as transmitted (or reflected) light. In this study, we introduce a new PAS setup that employs an oblique-incidence laser to study extrinsic chirality of metasurfaces made of polystyrene nanospheres asymmetrically coated with Ag. Our experimental results reveal intriguing CD trends dependent on the angle of incidence and wavelength, indicative of extrinsic chirality. This study expands the application of PAS, enabling simultaneous analysis of multiple wavelengths and providing valuable insights into chiral metasurfaces.

Conventional methods for producing superhydrophobic passive daytime radiative cooling coatings are considered inexpensive, however the majorities use fluorinated polymer. In this work a novel method, fluorine-free, developed for synthesizing porous structures coating by using low density polyethylene is presented. The method has precise control over the thickness and microstructure. Moreover, the materials and the machinery required to produce the coatings are minimal in comparison to the conventional methods, hence lowering the cost of production. The coating, poly-cool, exhibits superhydrophobic properties as well as radiative cooling capabilities with solar reflectance of 97.4% and emissivity of 91% within the atmospheric window. The coating consists of highly porous polyethylene and PDMS nanoparticles. The high porosity of polyethylene helps improve the reflectivity of solar irradiance whereas the PDMS nanoparticles tune the emissivity of the coating to match that of the atmospheric window (8 to 13m).

The performance of radiative coolers are directly affected by their constituting materials’ optical properties and micro-structures. Here, we investigate the effects of optical properties and microstructure on radiative cooling performance, namely solar reflectance and emittance at 9-13 µm region. The aim is to provide guidance to reach the ideal radiative cooler. Inspected phenomena are included but not limited to Mie resonance, light scattering, effective medium theory.

Daytime radiative cooling has emerged as a promising solution for continuous passive cooling. While significant progress has been made in material developments, questions persist regarding the potential large-scale deployment of this technology. Among the potential applications, two predominant uses of daytime radiative cooling materials are under study: passive roof cooling and water-cooling panels. Passive roof cooling involves the deposition of radiative cooling material on the roof’s surface to passively cool the building by reflecting incoming solar rays. The second application employs outdoor radiative cooling panels to passively cool water, which can be used to assist cooling systems. For instance, cooled water could sub-cool the cooling refrigerant, thereby improving the air conditioner's energy efficiency.

In the present study, a numerical assessment to compare the benefits of both application schemes for radiative cooling materials is conducted. For each application, the model predicts the energy savings achievable by each integration mode. Preliminary results indicate that prioritizing roof cooling applications would be most effective in tropical regions. The deployment of water cooling panels for refrigerant sub-cooling appears to be more beneficial in mid-latitude temperate zones. These findings suggest adjusted approaches based on climatic considerations for the optimal deployment of daytime radiative cooling technologies worldwide.

Remote sensing in thermal infrared bands (TIR) is largely dominated by cumbersome dispersive-type hyperspectral imagers, which usually require expensive and cryo-cooled quantum detectors to make up for their low optical throughput. Here, we present a compact and low-cost TIR hyperspectral camera based on the Fourier-transform approach. It combines an uncooled bolometer detector and a common-path birefringent interferometer made of calomel (Hg2Cl2). It features high optical throughput, an interferometric contrast greater than 90% even for incoherent radiation, spectral resolution tunable up to 4.5 cm-1, robust and long-term interferometric stability. Retrieving in a few minutes the infrared spectrum in all pixels of the TIR image, it could constitute a valuable tool for evaluating radiative cooling materials' spatial and spectral properties over extended areas. We test the capabilities of the instrument by measuring the emissivity map of different butterfly wings, which provide a natural example of radiative cooling.

The development of optical systems has a very long tradition, and innovation in this field is accelerating. From an optical design perspective, for example, the use of free-form surfaces and adaptive optics is opening up new possibilities in the architecture and design of optical systems. One key for innovation is to understand the special features of new technologies including their limitations. We present an optical architecture using adaptive freeform optics to enable a new type of fluorescence microscopy.

Multiple researchers have explored the use of 3D printed micro-optical components as interfaces to quantum point emitters by considering different designs and configurations. Typically, these designs involve parametric structures optimized in combination with idealized point source models, which is the standard approach used in the realization of imaging systems. By restricting the light emission into a limited angular extent, small NA optical beams can be obtained. This results in an increased photon collection efficiency by centimeter-scale optical objectives in comparison to the case of bare point emitters. However, although low NA beams can be obtained in this form, this does not guarantee that the obtained field profiles will match the required spatial distribution needed for maximizing the coupling of photons into single mode fibers. In our work, we propose a different approach for maximizing such a spatial field overlap condition. In order to realize this, we rely on well-known numerical routines used in the context of illumination design tasks. Finally, we compare the obtained designs to standard parametric 3D printed based interfaces, which have been used in the context of 3D printed micro-optical interfaces to single photon sources.

In this paper, we present a highly miniaturized static projection system for integrated optical applications. Our system, which is only the size of a grain of salt, is 3D-printed using a single two-photon lithography step, enabling easy integration with photonic chips or optical fibers with high alignment accuracy and low process complexity.

Unlike conventional projection slides that use a transmission function to locally absorb or block light, our approach requires an all-transparent approach to be printable using a single transparent resist material. To achieve this, we established a partially coherent projection principle that partly directs light out of the acceptance etendue, allowing us to generate gray values across the field of view and achieve all-transparent projection slides.

Our miniaturized projection system has significant potential for various applications, including metrology, sensing, and endoscopy. We believe that our work provides a significant advancement in the field of integrated optical systems and opens up new possibilities for a wide range of applications.

In recent years, 3D machining in glass for micro-components has seen a notable boost, notably with the development of a novel optical fabrication chain. This approach uses lasers for shaping and polishing, enabling the creation of complex mini-optics efficiently.

The process begins with selective laser-induced etching (SLE) to define the optics' outer shape and surface figure. Subsequent polishing, using a "one-shot laser polishing" technique, removes imperfections and reduces roughness in a single step, achieving optical-grade smoothness.

This fabrication chain is applicable to mini-aspheres as well, enhancing their production efficiency. Additionally, it allows for wafer-level production, where multiple mini-optics are interconnected on a single glass substrate. The innovative SLE wafer-level approach optimizes heat flow during polishing, ensuring uniformity and superior optical quality.

Freeform metal optics are critical components in advanced optical systems for applications ranging from laser technology to space exploration. Accurately measuring mid-spatial-frequency roughness (MSFR) on these surfaces is essential for ensuring optimal performance and quality control. We present a cost-efficient, high-precision deflectometry system designed to meet this crucial metrology need.

Our system utilizes a novel calibration method and surface reconstruction workflow to achieve nanometer-level precision in measuring mid-spatial-frequency roughness of freeform mirrors. The key components include a low-cost, lightweight, and compact-sized camera and display. We discuss the challenges in accurately calibrating the intrinsic and extrinsic parameters. We then describe our measurement approach, which employs a combination of Gray-code and sinusoidal patterns that are observed by the camera through the reflective surface. Finally, we present our algorithm for surface reconstruction based on phase difference minimization and compare our deflectometric results with those of interferometric measurements.

Our sensor demonstrates high accuracy in characterizing MSFR while offering advantages in cost and flexibility compared to conventional techniques. The system has potential applications in autonomous production architectures for efficiently manufacturing and inspecting multiple mirror components, addressing the demand for high-quality optical elements in various industries.

ARTEMIS proposes fundamental research toward the development of integrable single and entangled photon sources based on metallorganic molecular compounds. The project is motivated by the urgent need for novel quantum sources with unprecedented versatility, flexibility and performance. This goal will be pursued by resorting to molecular materials, based on transition metal and/or lanthanide ions with organic moieties, characterized by tunable linear downshifted emission as well as non-linear optical properties enabling on-demand single photons and entangled photon pairs/triplets generation. Such flexible and processable metallorganic materials will replace traditional quantum photon sources based on bulk inorganic crystals allowing for the direct integration of wavelength-tunable quantum sources on current devices. The molecular quantum sources will be combined with suitable designed plasmonic supernanostructured cavities to achieve the highest optical enhancement. The

proposed progress will be gained through cutting-edge synthesis techniques and advanced characterization methods integrated with nano-photonics engineering strategies. The devices and methods developed in this project will lead to photon sources with competitive performance in terms of coherence, e iciency, scalability, and cost. This will lead to a fundamental breakthrough in the development of quantum technologies, paving the way to bring them out of the laboratory into the real world.

Project website: https://www.artemis-quantumproject.eu

Ultrashort laser pulses are prominent enabling tools in countless advanced applications, ranging from fundamental research to medical and industrial use. However, despite a number of established techniques, straightforward characterization of ultrashort laser pulses has remained a nontrivial task. The project SISHOT, funded by the European Innovation Council, focuses on the development of advanced ultrashort laser pulse characterization based on the dispersion scan (d-scan) technique. In particular, two d-scan implementations, capable of characterizing ultrashort laser pulses in single-shot operation, are being further developed to meet the needs in academy and industry. SISHOT builds on the outcome of previous proof-of-concept projects, funded by the European Research Council. It is driven collaboratively between the research group for attosecond physics at Lund University in Sweden and the deep-tech company, Sphere Ultrafast Photonics, located in Porto, Portugal.

A cornerstone for the future of experimentation, simulators allow real-world scenarios and conditions to be explored without the associated risks, costs, or time restrictions imposed by the real world. Integrating the nature and behavior of matter and energy on atomic scales creates a more authentic virtual world in which simulations can run following the rules of quantum mechanics to model new smart materials, predict chemical reactions, or solve high-energy physics problems. However, the ways to access quantum behaviors are often hampered by the need for complex conditions and costly solutions. The EPIQUS project, funded by the EU Horizon 2020 – FET initiative, is creating a lab-accessible and affordable quantum simulator (QS) operable at room temperature. Such a QS has the potential to provide many advantages including supporting rapid and widespread innovation.

2DNeuralVision is an EU project that brings together 7 European research centres, leading universities, and innovative companies from 4 different countries to develop the enabling components for a low-power consumption, computer vision system that could be used for adverse weather and low light conditions.

Optical coherence tomography (OCT) is a key imaging technology, especially for ophthalmology, allowing noncontact high resolution 3D imaging which has helped to save the sight of millions of people across the world. OCT developed rapidly since its invention in 1991 but has stalled since reaching the practical axial resolution (∆z) limit of ~1 μm (>5 μm for most commercial systems). Quantum OCT (QOCT) offers a potential factor of two improvement in ∆z together with greatly reduced sensitivity to dispersion. By employing the orbital angular momentum (OAM) as an additional quantum degree of freedom in QOCT, the project aims to protect the system from environmental noise and furthermore to deliver improved edge definition and surface profile.

QSNP is a European Quantum Flagship project that aims to develop quantum cryptography technology to secure the transmission of information over the internet.

QSNP will contribute to the European sovereignty in quantum technology for cybersecurity protecting the privacy and the sensitive information of European citizens transmitted over the internet.

Micro-Spatially Offset Raman Spectroscopy (micro-SORS) is an advanced Raman technique that allows the non-destructive analysis of inner portions of cultural heritage artefacts, providing insights on their composition in a non-destructive way. The contribution delves into the methodological and technological advancements of micro-SORS at the CNR-ISPC Raman Spectroscopy Laboratory in Milan over the past decade. Developed in 2014, micro-SORS has become a versatile tool for characterizing artefacts from various historical periods and cultural contexts. Significant progress has been made in refining instrumentation and methodology, resulting in high-performance micro-SORS prototypes, including benchtop and portable systems. Key topics focus on investigating layered materials (e.g., paintings and painted objects) and studying the diffusion of conservation treatments and decay products into various substrates. The aim is to obtain information about the materials' composition, the efficacy of treatments, and the conservation state of the objects under analysis. Additionally, mapping/imaging micro-SORS has been developed to reconstruct the distribution of compounds hidden by opaque layers, such as concealed text in sealed letters. Lastly, this presentation will cover challenges associated with in-situ micro-SORS analysis, including environmental constraints and data interpretation, and will explore strategies for overcoming these.

Ultramarine Blue (UB) pigment, derived from lapis lazuli, holds a significant place in the history of late medieval and Renaissance Europe, owing to its unusually bright colour and stability. Its prohibitive price, which equalled that of gold, meant that it was only used by estimated artists. In this work we present a non-invasive, multimodal approach to the characterization of the photoluminescent properties of different variants of the pigment. The ultimate goal of this research is to propose a protocol for the identification of UB in artworks thanks to the combination of Raman spectroscopy and time resolved-photoluminescence spectroscopy and imaging.

The 1960s saw the emergence of plastic as an indispensable component in various fields, including art and design. Acrylonitrile-butadiene-styrene (ABS) is widely used by artists and designers for a range of applications including sculptures and decorative pieces. Consequently, the necessity to conserve ABS from deterioration is a crucial issue in the field of cultural heritage preservation. Many studies have highlighted the criticality of the stability of the polybutadiene component when exposed to light. We propose a new multimodal spectroscopic approach to assess the conservation status of plastic design objects. This nondestructive approach combines correlative Brillouin and Raman micro-spectroscopy (BRaMS),

external reflection IR spectroscopy and portable NMR relaxometry. BRaMS is a novel nondestructive technique in the field of heritage conservation, allowing simultaneous monitoring of chemical and mechanical changes occurring at the sample surface. The present study focused on photochemically aged LEGO® bricks made of ABS and aimed to i) correlate chemical and mechanical changes induced by light exposure and ii) introduce a surface degradation index (SDI), measurable in situ by external reflection IR spectroscopy, to assess the state of conservation of plastic artefacts. Finally, non-invasive investigations were carried out on real design objects using the MObile LABoratory (MOLAB) platform.

This study explores the use of hyperspectral imaging (HSI) to monitor the effectiveness of plasma-generated atomic oxygen (AO) treatment for non-invasive cleaning of cultural heritage object. Silk samples dyed with indigo blue, including those soiled with soot to mimic historical artifacts, were treated with plasma-generated atomic oxygen for varying durations. Using HSI with a TWINS birefringent interferometer, diffuse reflectance and light-induced fluorescence are observed. That allowed a precise evaluation of sample degradation avoiding any invasive sample extraction. This research not only contributes to the field of cultural heritage conservation but also enhances understanding of indigo colour degradation processes and the evaluation of non-invasive cleaning techniques on sensitive materials.

Terahertz time-domain spectroscopic ellipsometry (THz-TDSE) provides several advantages and opens a wide range of applications in optical metrology. We demonstrate the measurement of complete ellipsometric spectral response in terms of the Jones or Mueller matrix based on polarization switching by using a spintronic THz emitter (STE). The general method is demonstrated on THz-TDSE of anisotropic crystal of Mercury Chloride (Calomel). Applications of THz-TDSE in the field of THz optical activity and contactless measurement of surface electric properties are proposed.

An imaging Mueller matrix ellipsometer is used to measure structures in measuring fields in the micrometre range, which are too small for conventional ellipsometry. Line and grid structures are measured and evaluated with the help of numerical simulations using the finite element method to characterize the structure parameters.

We present the impact of line edge roughness (LER) on the optical critical dimension (OCD) metrology of nanostructures. The consideration of LER in OCD requires numerically expensive forward models and is therefore usually neglected. We present an analytical approach that allows estimation of the impact on the uncertainty. Systematic differences between CD measured by SEM and OCD were observed in different experiments. While SEM is basically sensitive to the local volume density, optical methods are sensitive to the permittivity of the material. We discuss an analytical upper bound on the contribution of the LER. For high index gratings, the contribution is as high as 3.7 nm for TM-polarized light and 1.2 nm for TE-polarized light, making this crucial for sub-nanometer metrology.

Gold gratings were measured by spectroscopic ellipsometry and modeled by the finite element method to investigate the capabilities of optical dimensional metrology for plasmonic diffractive structures. The gratings were prepared by electron beam lithography using parameters determined by finite element simulations for significant variations of the amplitude ratio and phase shift of the polarized reflection coefficients to achieve high sensitivity for both the measurement of the grating dimensions and the sensing capabilities. Sub-nanometer sensitivity was shown to determine the grating dimensions and the thickness of an adsorbed layer to be detected in both traditional reflection and Kretschmann-Raether (KR) configurations. The sensitivity for the refractive index of the ambient was calculated to be 10$^{-5}$ at best, which is not significantly better than the sensitivities for plane gold layers in KR configurations. However, in diffraction-based resonant setups, the high sensitivity dips can be shifted to a larger spectral range, which is highly significant in many applications. It was also revealed that 2D models assuming a perfect geometry fit the measured ellipsometry spectra only qualitatively, leaving room for model development in the future.

In the pursuit of closing the gap between nanometrology and nanofabrication, we investigate the use of advanced optical far field methods for sub-wavelength parameter reconstruction. With the goal of establishing a hybrid evaluation scheme connecting different methods and including different information channels, we performed comparison measurements on a silicon line grating sample with buried as well as not buried surface relief lines. To this end, the results of our measurement are in good agreements with each other, and the collected structure data is feasible to be used for hybrid evaluation.

In this contribution, we will present our latest work around on-chip spectroscopy and sensing, using either silicon (Si) or silicon nitride (SiN) Photonic Integrated Circuits (PICs). The potential of such sophisticated, yet inexpensive approaches significantly improves the prospect of being able to deliver improvements in e.g. healthcare and security applications. This talk will highlight a number of specific examples of our recent work, including a hybrid (2D-graphene oxide, GO) integrated Si MRR, operating around 1550nm and capable of the sensitive detection of a range of vapour phase volatile organic compounds (VOCs), a hybrid (2D-graphene) integrated SiN device, operating around 800nm, capable of waveguide-based evanescent excitation/collection of Raman scattered light and a compact spectrometer based on a disordered Si multi-mode interferometer (MMI), with a spatial- and spectral-dependent speckle pattern that enables us to reproducing arbitrary input signals

In this presentation, I will provide an overview of the different technologies used to integrate III-V materials on silicon photonics to develop on-chip lasers, amplifiers and electro-absorption modulators. I will also discuss the challenges associated with each integration technology supported by different use-cases. Finally, I will share my vision on the existing opportunities for these emerging technologies to increase their maturity and readiness level for industrialization.

On-chip optical cavities play a crucial role in communications, sensing, quantum and nonlinear optics applications. State-of-the-art implementations are limited by trade-offs between quality factor and free-spectral range (FSR). Here, we introduce a novel approach for implementing topological photonic cavities by leveraging Zak phase engineering of Bragg gratings in silicon waveguides. We demonstrate cavities with a single resonance and a higher quality factor Q compared to of conventional Fabry-Pérot cavities, while at the same time overcoming FSR limitation of the latter.

The article presents an innovative approach to confining waves in planar high contrast grating hollow core waveguides, design achieves a surface that reflects waves effectively while maintaining a structure that allows for high transmission. The unique side-opened waveguide system also allows for gas flow through the sidewalls, making it uniquely suitable for gas spectroscopic techniques. The HCW design is specifically tailored for methane gas sensing at a wavelength of 3.27 µm. Numerical analysis shows that the transmittance can reach up to -0.41 dB. These findings demonstrate the potential of high-transmitting hollow-core waveguides for gas sensing, highlighting the effectiveness and cost-efficiency of chip-scale photonic integration in addressing energy and environmental challenges.