bluuebunny/crossref_metadata_2025 huggingface dataset:
Organisms-on-a-chip
Authors: Raimondi Manuela Teresa
Published: October 2024

The progression of fibrosis is frequently related to a failed healing process, and it may affect many tissues and organs causing severe consequences including post-infarct heart insufficiency, post-injury limb paralysis, cirrhosis, nephropathy, retinopathy, failure of implanted devices and even resistance to chemotherapy in solid tumours. Experimental models, both in vitro and in vivo, are widely used for studies of basic pathophysiology, and for pre-clinical testing of pharmacological therapies counteracting fibrosis. However, conventional models are not able to realistically reproduce the revascularization aspect of the inflammatory reaction that leads to the generation of fibrotic tissue. In this talk, I will present the most advanced frontier in this sector, represented by the new concept of an “organism-on-a-chip”. This is a hybrid model, in which an organ-on-a-chip is implanted sub-cute in a living organism, such as a mouse or an embryonated avian egg, thus eliciting a foreign-body reaction with the formation of a fibrotic microenvironment. In an organism-on-a-chip, the fibrotic reaction can be guided using microscopic scaffolds incorporated in the implanted chip. The fibrotic microenvironment can then be imaged longitudinally, in high resolution, in single and multiphoton optical microscopy, with the added advantage of significantly reducing animal sacrifice. The optical measurements performed in the platform address parameters of the extra-cellular matrix (stiffness, collagen density, collagen orientation, coefficient of diffusion) and vascularity (number of blood vessels, length, blood velocity and vessel permeability).
Full Stokes polarimetry based on the polarization-holographic diffraction element of an optimal configuration
Authors: Kilosanidze Barbara , Kakauridze George , Chaganava Irakli , Dadivadze Vladimir , Mshvenieradze Yuri
Published: October 2024

The new polarization-holographic element of an optimal configuration is developed for the real-time complete analysis of the polarization state of light (for determining all Stokes parameters). The simultaneous measurement of the intensities in all points of images in diffracted orders using CCD camera and appropriate software allows to determine the spatial distribution of a polarization state in the images of objects, and also the dispersion of this distribution.
Imaging Mueller matrix ellipsometry measurements on measuring fields in the micrometre range
Authors: Grundmann Jana , Bodermann Bernd
Published: October 2024

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.
Investigations on Diamond-NV-Centers as Alternative Labels in STED Microscopy
Authors: Nouri Mohammad , Harm Gunilla , Olivero Paolo , Voß Tobias , Kroker Stefanie , Bodermann Bernd
Published: October 2024

We investigate diamond nitrogen-vacancy (NV) centers as alternative labels in stimulated emission depletion (STED) microscopy. To this end, artificial diamond is used as a substrate and Raman spectroscopy in photoluminescence (PL) mode is performed for clearly identifying the emission wavelengths of the NV centers. With the aid of a STED microscopy system, we imaged a random feature on substrate surface with the NV-centers in STED and confocal mode. Our first measurements indicate that the combination of NV centers and STED is very promising for resolving the structures and can be further extended to nanoscale structures applied on the diamond substrates.
Inflatable On-Axis and Off-Axis Space Telescope Designs
Authors: Kim Daewook , Kim Youngsik , Choi Heejoo , Takashima Yuzuru , Walker Christopher
Published: October 2024

In the realm of astronomical scientific exploration, deployable and scalable approaches in space telescope systems are reshaping our understanding of the universe. Two revolutionary membrane-based space telescope designs, on-axis OASIS (Orbiting Astronomical Satellite for Investigating Stellar Systems) and off-axis SALTUS (Single Aperture Large Telescope for Universe Studies), have been developed as mid/far-infrared telescope concepts featuring an inflatable primary mirror. Through the scalable primary aperture design, these deployable space telescopes leverage an all-encompassing optical architecture that taps into the uncharted potential of extremely large telescope apertures. These visionary mission and optical designs pave the way for the next generation scalable telescopes of unprecedented dimensions and diffraction-limited imaging resolutions.
Analytical model for dispersion measurement in integrated waveguides using michelson interferometry effects
Authors: Yorke Isaac , Girouard Peter David , Galili Michael
Published: October 2024

We present an analytical model for measuring the dispersion of integrated waveguides, leveraging the Michelson interferometry effects observed in devices with chirped Bragg gratings. Building on our previous experimental work, we derived a theoretical framework that simulates the group delay and subsequent dispersion values from the reflected spectrum of a device under test (DUT) which is a linearly chirped Bragg grating fabricated on a silicon-on-insulator (SOI) platform. This model incorporates the principles of interference fringes generated by reflections within the waveguide, enabling a precise calculation of group delay (τ) in the DUT as a function of frequency. Our model predicts the dispersion by determining the spacing between the peaks (Δf) from the local period of the interferometric fringes, with τ being inversely proportional to Δf. Simulations were conducted on a DUT that is designed to produce a dispersion of -45.9 ps2. The model yielded a dispersion of -45.6 ± 0.67 ps2, demonstrating close alignment with both the theoretical design and our experimental results, which recorded a dispersion of -45.5 ± 11.2 ps2 from 7 different DUTs that were measured.
Investigations into temperature measurement in a laser-based heating process of optical, machined components
Authors: Henkel Sebastian , Knoche Daniel Paul , Güpner Michael , Koch Sarah , Schulze Christian , Boeckh Thekla , Bliedtner Jens
Published: October 2024

The manufacturing of optical components is subject to constant efforts to optimise production processes in order to achieve high surface qualities under the most economical conditions possible. This includes the refinement of existing technologies or development of completely new production technologies. One possible approach is the combination of conventional machining processes for optical components like diamond turning, grinding or polishing with laser-based processes to thermally influence the surface for improved machining or surface properties. For this, knowledge of the thermal interactions of the laser on the component surface is needed, which in turn requires its metrological acquisition. In this work, measurements were carried out using various methods for the controlled heating of glass surfaces by an infrared laser (λ=1070 nm). Among other things, a clear correlation between the samples surface roughness and the laser absorption is found.
Scratch healing with CO2 Laser on fused silica for surface repair
Authors: Walder Simon , Lammler Sven , Filipec Dominique , Cattaneo Heidi , Henkel Sebastian , Schulze Christian , Schulteiß Denise , Frank Samson , Fahnlc Oliver , Blicdtncr Jens
Published: October 2024

To prevent the disposal of minimally damaged lenses that fall outside the acceptable scratch and dig tolerance levels, an experimental study was conducted to repair mechanical scratches on a fused silica surface. The scratches were created using a diamond tip and then repaired using a CO2 laser. Various loads on the diamond lip and laser output power were tested. The transmission changes and subsurface damages were analysed. The surface quality analysis was performed using a white light interferometer, while the subsurface damage analysis was performed using optical coherence tomography. Local absorption differences can be quantified using photothermal deflection. To significantly enhance local transmittance, brittle and ductile scratches of various depths have been successfully healed.
SwissVAMyKnife.jl: An open-source package for tomographic volumetric additive manufacturing
Authors: Wechsler Felix , Gigli Carlo , Madrid-Wolff Jorge , Moser Christophe
Published: October 2024

We introduce an optimization framework for ray and wave optical tomographic volumetric additive manufacturing (TVAM). In TVAM, tomographic patterns are projected with a light modulator onto a photocurable resin from different angular directions. Once an energy dose threshold is crossed, the resin starts polymerizing. Current approaches assume a ray optical model for light propagation, using the Radon transform as backbone, which breaks down for small features in the region of 20 μm. In this work we describe how a wave optical framework allows to optically print smaller feature sizes. The optimization framework is written in the programming language Julia and allows for high-performance optimization of ray or wave optical based patterns for volumetric additive manufacturing.
Transient Structural, Thermal and Optical Performance (STOP) Analysis with Accelerated Thermomechanical Computation
Authors: Kurcsics Mark , Hahn Luzia , Eberhard Peter
Published: October 2024

Mechanical and thermal disturbances in optical systems are attracting increasing attention as accuracy requirements rise. For this reason, it is necessary to consider these disturbances at an early stage in the design process. This can be done by a holistic multiphysical opto-thermo-mechanical simulation. Such an approach is presented with a focus on efficient thermomechanical computation through a quasi-static approximation.
Decoupled illumination detection in light sheet microscopy for 4D observation of spermatozoa at high-resolutions
Authors: Licea-Rodriguez Jacob , Castro-Olvera Gustavo , Palillero-Sandoval Omar , Merino Gonzalo , Eriksen Martin , Beltrán-Vargas Roberto , Rocha-Mendoza Israel , Olarte Omar E. , Loza-Alvarez Pablo
Published: October 2024

We present the use of wavefront coding (WFC) combined with machine learning in a light sheet fluorescence microscopy (LSFM) system. We visualize the 3D dynamics of sperm flagellar motion at an imaging speed up to 80 volumes per second, which is faster than twice volumetric video rate. By using the WFC technique we achieve to extend the depth of field of the collection objective with high numerical aperture (NA=1) from 2.6 μm to 50 μm, i. e., more than one order of magnitude. To improve the quality of the final images, we applied a machine learning-based algorithm to the acquired sperm raw images and to the point spread function (PSF) of the generated cubic phase masks previous to the deconvolution process.
Development of a Microfluidic Device for Blood Cells Extraction in Liquid Biopsy
Authors: Caragnano Stefania , Rodriguez Villarreal Angeles Ivon , Terre Jasmina Casals , Petruzzellis Isabella , Ancona Antonio , Osellame Roberto , Vázquez Rebeca Martínez , Volpe Annalisa
Published: October 2024

This project aims to produce a microfluidic device capable of separating 6 μm and 20 μm diameters particles by inertial sorting. This Lab-on-Chip (LoC) was designed with a trapezoidal cross-section for better fluid control and effective particle manipulation at the microscopic level, as demonstrated by COMSOL simulations. The device was manufactured on a substrate of Polymethyl Methacrylate (PMMA) by femtosecond laser technology and then assembled using an innovative geometry-preserving Isopropyl alcohol-based procedure. The LoC was test with spherical plastic microparticles of two diameters (6 μm and 20 μm) suspended in distilled water. The separation efficiencies were (98.2 ± 1.6) % for 20 μm diameter particles and (70.0 ± 1.8) % for 6 μm diameter particles in good agreement with the simulation results. Finally, after a microfluidic channels’ acetone vapors treatment, the device demonstrated a good ability to separate biological particles (Red Blood Cells) at different concentrations (20%, 30%, 40%, 50%) in a PBS buffer.
Innovative Photodynamic Strategies for Antimicrobial Treatments: Biosafety and Effectiveness in a Cnidarian Model
Authors: Blasio Martina , Iencharelli Marika , Costantini Paolo Emidio , De Felice Vittorio , Saporetti Roberto , Tino Angela , Di Maria Francesca , Danielli Alberto , Calvaresi Matteo , Tortiglione Claudia
Published: October 2024

Thiophene-based materials (TMs) have emerged as promising candidates in the field of photodynamic therapy (PDT) as photosensitizers agents owing to their remarkable electron transport properties, which facilitate efficient energy transfer processes crucial for PDT. In detail, TMs exhibit favourable optical characteristics, making them suitable candidates for the absorption and conversion of light energy into reactive oxygen species (ROS), thereby inducing cytotoxic effects in targeted cells. Recent studies have explored natural carriers, including proteins and phages, for enhanced cell uptake and permeation of photosensitizers, thereby enabling the induction of apoptosis across various cell lines. Despite the remarkable potential of this approach for PDT purposes, clinical translation necessitates in vivo models to validate these innovative tools. Here, we investigated the nanosafety and in vivo efficacy of these phototheranostic agents using the tissue-like animal model Hydra vulgaris. The transparency, softness, structural simplicity, and ethical neutrality of Hydra collectively render it an exemplary model for such inquiries. These features facilitate rapid screening of cytotoxicity and the effectiveness for photodinamic purposes.
Microbubble resonators for photoacoustic and photothermal characterisation of nanoparticles suspensions
Authors: Frigenti Gabriele , Cavigli Lucia , Ratto Fulvio , Centi Sonia , García-Fernández Tupak , Farnesi Daniele , Pelli Stefano , Nunzi Conti Gualtiero , Soria Silvia
Published: October 2024

We discuss the implementation of Whispering Gallery Modes Microbubble resonators (MBRs) as unique platforms for photoacoustic (PA) detection and photothermal (PT) spectroscopy. In a first experiment, the MBR transducer allowed to detect the PA signal generated by a suspension of gold nanorods (GNRs) within its core, leveraging on the MBR sharp optical spectrum and high sensitivity towards mechanical perturbations. Both static and flow-cytometry configuration were tested, finding that the MBR mechanical modes help detection by decoupling the environmental noise from the PA oscillation. In a second experiment, the MBR transducer allowed to reconstruct the GNRs absorption spectrum through the photothermal (PT) conversion, leveraging on high sensitivity towards temperature variations. We verified the scattering-free nature of the detection by using milk-stained GNRs suspension. We also found that the active locking of the MBR resonance increases the system sensitivity by an order-of-magnitude. These results make MBRs interesting candidates for combined PA and PT characterisation of extremely small samples for medical diagnosis, quality controls in food safety and chemical production processes.
Pleurosigma strigosum diatom frustule as a natural, multi-functional photonic platform
Authors: De Tommasi Edoardo , Rea Ilaria , Ferrara Maria Antonietta , De Stefano Luca , Al-Handal Adil. Y. , Stamenković Marija , Wulff Angela
Published: October 2024

Nature provides various organisms with ordered or quasi-ordered dielectric nanostructures that enable several animals, plants, and protists to manipulate light, optimizing inter- and intra-species communication, camouflage, or solar light harvesting. In particular, diatom microalgae possess nanostructured silica cell walls, known as frustules, which efficiently interact with optical radiation through multiple diffractive, refractive, scattering, waveguiding, and frequency down-conversion mechanisms. These properties contribute to diatoms’ efficiency in photosynthesis, UV tolerance, and possibly influence the phototaxis mechanisms of motile species. In our study, we utilized several imaging, spectroscopic, and numerical techniques to explore the optical functionalities of individual frustule components in the pennate, motile diatom Pleurosigma strigosum. We discuss the implications of frustule photonic properties on the living cell, and envision the exploitation of these properties in multifunctional, bio-derived photonic devices.
Exceptional points with waveguide-coupled nanolasers
Authors: Madiot Guilhem , Loren Patricia , Bazin Alexandre , Chateiller Quentin , Sagnes Isabelle , Beaudoin Grégoire , Pantzas Konstantin , Raineri Fabrice
Published: October 2024

Exceptional points (EPs) attract lots of attention due to the richness of the phenomenology associated to their presence in the complex eigenspectrum of coupled non-Hermitian systems. Here we provide both a coupled mode theory analysis and an experimental investigation of two nanolasers interacting through a channel-mediated coupling. We demonstrate the transition from Parity-Time (PT) symmetric to PT-broken regime using a thermo-optic control over the laser frequency detuning
Maximizing Fluorescence Enhancement in Metal Nanoantenna Arrays for efficient bioanalytical devices
Authors: Lospinoso Daniela , Colombelli Adriano , Creti’ Arianna , Cesaria Maura , Lomascolo Mauro , Rella Roberto , Manera Maria Grazia
Published: October 2024

Our investigation focused on fluorescence enhancement mechanisms using metal nanoantennas with Alexa Fluor-647. By exploiting numerical modelling tools, we fabricated non-interacting Au nanodisc arrays on glass substrates, achieving a maximum fluorescence enhancement factor of 180 at an optimal spacer thickness of approximately 10 nm. Comparative analysis with bare glass substrates revealed significant improvements in excitation and emission dynamics, attributed to nanoscale field confinement and the Purcell effect. Time- and space-resolved photoluminescence measurements unveiled a distance-dependent interaction between the fluorophore and localized plasmons, modulated by thin polyelectrolyte monolayers, with prevalent radiative processes in samples exhibiting maximum signal.
Device characteristics of alternating-current-driven colour-tunable phosphorescent organic light-emitting diodes
Authors: Hwang Yeonsu , Lee Hyunkoo
Published: October 2024

We demonstrate alternating-current (AC)-driven colour-tunable organic light-emitting diodes (OLEDs) with vertically stacked green and red phosphorescent OLED units. Optically optimized thicknesses of hole and electron transporting layers were investigated through optical simulation. In addition, two types of red host materials were used for the red OLED unit, and the red OLED unit with 4,4′-Bis(N-carbazolyl)-1,1′-biphenyl showed higher current efficiency compared to that of the red OLED unit with 2,6-Bis(3-(9H-carbazol-9-yl)phenyl)pyridine. The fabricated colour-tunable exhibited red and green colours when the duty ratio was 1% and 99%, respectively. Furthermore, the device can produce various colours that are a mixture of green and red by adjusting the AC-driving duty ratios.
High-power intracavity upconversion pumped Tm:YLF laser emitting at 2.3 μm
Authors: Dupont Hippolyte , Lenfant Timothée , Guillemot Lauren , Delen Xavier , Loiko Pavel , Braud Alain , Loiseau Pascal , Viana Bruno , Georges Thierry , Georges Patrick , Camy Patrice , Druon Frédéric
Published: October 2024

A Tm:LiYF4 laser operating on the 3H4 → 3H5 transition is integrated into a high-power diode-pumped Nd:ASL laser for intracavity upconversion pumping at 1.05 μm. This architecture leads to a record-high output power at 2.3 μm ever extracted from any upconversion pumped Thulium laser. The continuous-wave Tm-laser yields 1.81 W at 2.3 μm at 32 W of laser-diode pump power at 0.8 μm, rivalling direct diode pumping. The intracavity pumping mitigates weak absorption inherent to the upconversion pumping scheme and disperses the deposited heat over two laser crystals. This laser design minimizes heating of the Tm-crystal and enhances the tolerance to Tm3+ excited-state absorption, being promising for high-power 2.3-μm solid-state lasers based on thulium ions.
In-situ characterization of the semiconductor-metal phase transition in vanadium dioxide thin films
Authors: Delbono Ilaria , Kalinic Boris , Scian Carlo , Cesca Tiziana , Mattei Giovanni
Published: October 2024

Vanadium dioxide (VO2) exhibits a reversible first-order semiconductor-metal phase transition (SMT) near 68 °C at ambient pressure, consisting in a structural transformation from a low-temperature semiconducting monoclinic phase to a high-temperature metallic rutile phase. This phenomenon is investigated on thin films of VO2, with thickness ranging from 15 to 300 nm, which are deposited on a silica substrate by magnetron sputtering. The films are systematically characterized at the morphological, structural, and optical level by using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Grazing Incidence X-ray Di↵raction (GIXRD), Raman Spectroscopy, Spectrophotometry, and Spectroscopic Ellipsometry. The SMT is investigated in-situ by Optical Spectroscopy in the VIS-NIR spectral range and by Grazing Incidence X-ray Di↵raction (GIXRD). Compared to their bulk counterpart, thin films display broader phase transitions upon thermal excitation. This is evidenced by monitoring the temperature-dependent transmittance at specific wavelengths which reveals a hysteretic behaviour, whose thermal width and amplitude depends on the film thicknesses. Additionally, changes in peak positions and intensities in in-situ GIXRD di↵raction spectra further elucidate the phase transition dynamics.
Optical properties and NIR Photoluminescence of Dy3+ doped CdS Q-dots dispersed in borosilicate glass for biophotonics applications
Authors: Kumi Barimah Eric , Liu Yinshen , Al-Murish Mohanad , Jha Animesh
Published: October 2024

We synthesised CdS Q-dots and Dy3+ doped CdS Q-dots dispersed in borosilicate glasses and evaluated their optical and NIR photoluminescence properties. When excited with an 800nm source, new strong photoluminescence emissions from 850 to 1150 nm were observed in the NIR are reported. These new find states may be attributed to NIR virtual or trap states of the CdS S-Qdot. The strong photoluminescence emission spectrum observed from 850 to 950 nm corresponds to electron–hole recombination for as-prepared CdS-Q-dot glasses. However, this photoluminescence emission disappeared upon heat treatment due to photoluminescence emission from defect states.
Optically smooth microchannels in the volume of lithium niobate fabricated by selective etching of fs-laser written structures and subsequent annealing
Authors: Nwatu Daniel , Kip Detlef , Hasse Kore
Published: October 2024

3D-hollow microstructures with few tens of micrometer in diameter with an optical-quality surface roughness (Ra ≤ 1 nm) have been fabricated in the volume of lithium niobate by selective etching of fs-laser written structures and post-etching annealing. The fs-laser writing parameters and the annealing process have been refined to reduce the average surface roughness and the shape change. Systematically investigating the annealing process, an empirical functional description of the temporal evolution of the surface roughness was found completing the data set of processing parameters for selective etching of fs-laser written structures, allowing to control the fabrication process of the hollow microstructures concerning both shape and surface roughness. Thus, our results represent another milestone within the research towards monolithic micro-(opto)fluidic applications inside the multifunctional crystal lithium niobate.
Raman Microscopy Identification of Secondary Spurious Phases in Molten GdSr2RuCu2O8-δ Superconductor for Photonics and Plasmonic Applications
Authors: Gombos Marcello , Managò Stefano , Zola Danilo , Carapella Giovanni , Tarallo Oreste , Mocella Vito , De Luca Anna Chiara , Rendina Ivo , Ruffo Francesco , Orgiani Pasquale , Ciancio Regina
Published: October 2024

Plasmonic and Photonics applications of superconducting materials, suggested at first by the necessity to minimize the dissipative losses of conventional metals in the high frequency ranges, are topics of growing interest in Optics. In this perspective, GdSr2RuCu2O8-δ (Gd1212) Rutheno-Cuprate Superconductor presents very promising properties, showing both superconducting and magnetically ordered phases coexisting in the same cell. To investigate its features, the fabrication of macroscopic crystallographically oriented samples is necessary. The use of melt texturing techniques has shown to be among the most effective ways to achieve the best characteristics, although the fabrication of high-quality Gd1212 samples is intrinsically difficult.

To reach a better understanding of Gd1212 incongruent melting reaction, a series of bulk samples annealed at temperatures below and above the melting temperature was prepared. Raman Microscopy and Mapping performed on molten and re-solidified samples revealed the presence of different phases, corresponding to those identified in our previous studies. These observations were also confirmed by XRD, TGA-DTA, and SEM+EDS characterisations. Secondary phases formation showed a strong dependence on the temperature of the annealing treatments.

Susceptibility and magnetization measurements show both superconducting and magnetic transitions and a contribution of different spurious magnetic phases as suggested by EDS.
Random Laser and Replica Symmetry Breaking in SiO2-Rhodamine 6G xerogel powder
Authors: Câmara Josivanir G. , da Silva Davinson M. , Ferretti Stefano , Gentilini Silvia , Conti Claudio , Ghofraniha Neda
Published: October 2024

Random laser (RL) based on Rhodamine 6G (Rh6G) doped silica xerogel, fabricated by a conventional sol-gel (SG) synthesis, was observed around 590 nm, in a large band typical from dye RLs. Different from other previous works, where the xerogel is just impregnated or infiltrated with a dye solution, here the Rh6G was added during the SG synthesis. The obtained material was grinded using a mortar and a pestle, and the resulting powder was carefully packed in a sample holder and pumped at 532 nm using a 6 ns pulsed laser. We used spectral and images measurements to perform statistical analysis and describe experimentally the Parisi replica breaking symmetry (RSB) phenomenon in a complex system. These results show that RSB obtained from image is a promising method for RL characterization. Indeed, by calculating the RSB maps, we demonstrate that the RL emission is not a homogenous process, depending on the scattering and gain properties of different regions.
Study of the defect in the CaF2 materials via a laser-induced fluorescence measurement
Authors: Guesmi Mariem , Thoř Tomaš , Procháska František , Taboubi Oumayma , Šeděnková Ivana , Žídek Karel
Published: October 2024

Analysis of defects in optical materials is crucial for their applicability in cutting-edge optical components. Since calcium fluoride (CaF2) is highly regarded for optical applications, understanding the nature of defects within CaF2 is particularly significant. These defects have been conventionally identified through absorption and photoluminescence (PL) emission studies. In this work, we investigate the defects by measuring laser-induced fluorescence (LIF) spectra over a long irradiation. By decomposing the PL spectrum into multiple Gaussian PL bands, we identify the defects within the CaF2 material. The measurement of irradiation-induced PL can be rationalized by the stabilization of F-centers via the formation of M-centers. PL mapping has been also studied to study the potential link between the surface oxygen contamination of CaF2 samples and polishing techniques.
UV coatings using Ta2O5-SiO2 quantized nanolaminates
Authors: Bärtschi Manuel , Waldner Stephan , Steger Fabian , Frei Thomas , Schwyn Thöny Silvia , Maeder Xavier
Published: October 2024

In the last few years, quantized nanolaminates (QNL) have become increasingly popular as a metamaterial in the development for optical coatings. Experiments were often performed using IBS or ALD coating techniques, which yield excellent accuracy but are very time consuming to coat. By using a magnetron sputter system with rotating substrate table, we are able to produce these layers at very high deposition rates and to use these nanolaminates as standalone high index material in optical designs. Due to the properties of QNL to increase the band energy and thus shift the absorption edge into lower wavelength ranges, it is possible to create designs in the UV range that would not be possible with simple Ta2O5-SiO2 material combination in regular designs. In this work we show a selection of different designs such as anti-reflective coatings, mirrors and short pass filters at wavelengths from 266-355nm which covers an important range in laser applications.
A universal broadband and CEP stable seeder for high-power amplifiers
Authors: Maksimenka Raman , Bux Simone , Alexandridi Christina , Bussière Benoit , Thiré Nicolas , Pinoteau Thomas , Falcoz Franck , Pertot Yoann
Published: October 2024

This work presents a universal seeder architecture based on filamentation and parametric amplification from an Ytterbium pump laser for the generation of pulses with versatile properties in terms of central wavelength, bandwidth, CEP, and contrast for seeding high power amplifiers based on various technologies.
High-order harmonic generation from ultrafast matter Talbot effect
Authors: Plaja Luis , García-Cabrera Ana , Hernández-García Carlos
Published: October 2024

High-order harmonic spectroscopy is a robust method for probing electron dynamics under the influence of a driving field, capturing phenomena as brief as attoseconds. It relies on the extreme non-linear process of high-harmonic generation (HHG), where intense laser pulses are directed at a material, causing it to emit high-energy photons in harmonics of the laser frequency. In this contribution we explore the possibility to generate high-order harmonics from low-dimensional crystalline solids driven under grazing incidence. We demonstrate that, in this unconventional geometry, the electron wavefunction is ejected from the solid and, subsequently, redirected to it to generate harmonics. Most appealingly, we show that the crystal’s periodicity imprinted in the electron’s wavefunction introduces a revival dynamics closely connected with the matter temporal Talbot effect. These Talbot oscillations are ultrafast (< femtosecond) and leave a distinct signature in the high-frequency harmonic spectrum, in the form of structures extending beyond the main spectral cutoff.
Narrow–linewidth tunable laser source for long-wavelength optical coherence tomography at 1700 nm
Authors: Szewczyk, Olga , Łaszczych Zbigniew , Soboń Grzegorz
Published: October 2024

We present a widely tunable laser source with narrowed linewidths at the level of 0.4 – 1.1 nm. The laser source incorporates a comb-profile fiber (CPF) which allows for spectral compression of the tunable optical pulses to the linewidths below 1 nm. The spectral compression factor is as high as 37.2 and is the highest obtained for this wavelength range. With the use of an electro-optic modulator (EOM), the laser system ensures rapid tuning up to 10 GHz. Together with the wide spectral range of 1600-1900 nm, and compressed spectral width, the source meets the requirements of the optical coherence tomography (OCT).
Design and Fabrication of a Photonic Integrated Circuit-based Entangled Photon Pair Source using Microring Resonators
Authors: ten Haaf Nienke , van der Vuurst Dave , Bakker David , Castro do Amaral Gustavo , Dalle Jacob , Schmits Ruud
Published: October 2024

Photonic integrated circuits (PICs) based on silicon-on-insulator (SOI) substrates provide a lightweight, compact platform for applications in quantum optics. We show the evaluation and characterization of an SOI-bascd PIC design for an entangled photon pair source, generating photon pairs by means of the nonlinear process of spontaneous four-wave mixing in microring resonators. Experimental results following from the chip fabrication fed back into the simulated parameter tuning effects, culminating in photon pair generation with measured correlations exceeding classically predicted limits.
Frequency comb generation dynamics in χ(2) + χ(3) AlGaAs microresonators
Authors: Talenti Francesco Rinaldo , Lovisolo Luca , Gerini Andrea , Parra-Rivas Pedro , Hansson Tobias , Wabnitz Stefan , Vivien Laurent , Alonso-Ramos Carlos , Leo Giuseppe
Published: October 2024

We propose an AlGaAs microring resonator design for the generation of an optical frequency comb by means of the interplay between harmonic generation and Kerr effect. Modal phase matching imposes specific waveguide geometries and, consequently, it impacts the nonlinear efficiency of the system. We show the dynamics of χ(2) + χ(3) comb generation resulting from type-I modal phase matching.
Resonant Fully Dielectric Metasurfaces for Ultrafast Terahertz Pulse Generation
Authors: Peters Luke , Rocco Davide , Olivieri Luana , Leon Unai Arregui , Cecconi Vittorio , Carletti Luca , Gigli Carlo , Valle Giuseppe Della , Cutrona Antonio , Gongora Juan Sebastian Totero , Leo Giuseppe , Pasquazi Alessia , De Angelis Costantino , Peccianti Marco
Published: October 2024

In the framework of optical frequency conversion, metasurfaces have elevated the potential for effective interfacial nonlinear coefficients through various modes of field localization. For the generation of pulsed ultrafast terahertz (THz) signals, metasurfaces present a viable alternative in the domain of surface-scalable sources driven by low-power oscillators (using nJ pulses). However, recent innovations have predominantly relied on surface plasmons (metals) and, more broadly, on excitations within non-transparency windows—conditions that typically impose limitations on applications and the choice of platforms. Here, we demonstrate the utilization of a fully-dielectric, fully transparent semiconductor that exploits surface-nano-structure-mediated resonances alongside its inherent quadratic nonlinear response. Our system exhibits a remarkable 40-fold efficiency enhancement in comparison to the non-decorated substrate.
Tailoring two-photon spontaneous emission: Framework and nanoantenna design for interference and directionality
Authors: Smeets Steve , Maes Bjorn , Rosolen Gilles
Published: October 2024

We develop a framework that computes two-photon spontaneous emission (TPSE) spectra of a quantum emitter near an arbitrarily shaped nanostructure. The model considers the interaction up to the electric quadrupolar order, which is relevant for nanophotonic structures sustaining strongly confined fields that are used to enhance and to tailor spontaneous emission processes. Moreover, we consider interference effects between multipolar two-photon emission channels, for the first time to our knowledge. First, we show for a s → s transition of a hydrogen atom placed under a silver plasmonic nanodisk a substantial enhancement in the photon-pair emission rates by 5 and 11 orders of magnitude for the two-electric dipole (2ED) and two-electric quadrupole (2EQ) transitions, respectively. Then for the same emitter under a plasmonic graphene nanotriangle, we demonstrate a breakdown of the electric dipole approximation in the TPSE process where the interference between the 2ED and 2EQ transitions is important, as it increases the total rate by 63 %. Third, we explore platforms where entangled photons of different energy are emitted in the far-field in different directions. In the end, our framework is a complete tool to design emitters and nanostructures for the TPSE process, leading to a rich assortment of functional nanoantennas.
Revisiting Temporal Coupled-Mode Theory in Ultrafast Physics: An Ab-initio Approach
Authors: Wu Tong , Lalanne Philippe
Published: October 2024

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.
Raman Gain in Transparent Nanostructured Glass-Ceramic
Authors: Pernice Pasquale , Sirleto Luigi , Rossi Manuela , Vergara Alessandro , Di Girolamo Rocco , Imparato Claudio , Aronne Antonio
Published: October 2024

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.
Free space whispering gallery mode microlasers as highly sensitive biosensors
Authors: Ferretti Stefano , Capocefalo Angela , Ceraolo Maria Grazia , Gentilini Silvia , Barolo Lorenzo , Baiocco Paola , Conti Claudio , Cortese Barbara , Bearzi Claudia , Rizzi Roberto , Ghofraniha Neda
Published: October 2024

High-precision biosensors for single or few molecules detection play a central role in numerous key fields, such as environmental monitoring and healthcare for early-stage disease diagnosis. In the last decade, laser biosensors have been investigated as proofs of concept, and several technologies have been proposed. Here we propose a demonstration of polymeric whispering gallery microlasers as biosensors for detecting proteins at low concentrations. Free space microlasers have the great advantage of working without any need for waveguiding for input excitation or output signal detection. The photonic microsensors can be easily patterned on microscope slides and operate in air and solution. We could detect down to 400 pg of protein without specific binding, and few tens of pg/mL with specific binding.
Light-field based 3D optical tweezers
Authors: Le Priol Etienne , Sasaki Atsushi , Beaucamp Anthony
Published: October 2024

Optical tweezers are designed to trap nano- and micro-scale particles. Once trapped, it is possible to move the particles but this requires complex mechanical adjustments to the optical system. In this paper, an easier way to trap and move multiple particles simultaneously is proposed, that uses a digital mirror-array and freeform micro-lens-array to generate several steerable optical traps inside a light-field.
Mode Coupling and Sensing in Plasmonic Layered Structures
Authors: Sekkat Zouheir
Published: October 2024

Optical sensors based on a plasmonic multilayer stack, such as metal-insulator-metal (MIM), have attracted considerable attention over the past decades owing to their high resolution and high performance compared to conventional surface plasmon resonance (CSPR) sensors for bulk sensing (BS) applications. In this paper we show that CSPR is better than MIM sensors for thin film sensing, i.e. when a dielectric sensing layer (SL) is deposited on the outermost metal layer of the structure. We demonstrate that the deposition of a thin film SL on the top of the outermost-layer of an optimized multilayer structure, i.e. MIM, strongly decreases the evanescent electric field and the field enhancement at metal-SL interface and decreases the sensor’s sensitivity for MIM versus CSPR. By considering the theoretical and experimental results we demontrated that CSPR is more suitable than MIM for thin films sensing applications.
A sensorised, microfluidic Ussing chamber manufactured by stereolithography and soft lithography techniques
Authors: Carnero Bastián , Radziunas-Salinas Yago , Rodiño-Janeiro Bruno K. , Rodrigues Patrícia M. , Ainla Alar , Xavier Miguel , Diéguez Lorena , Flores-Arias María Teresa
Published: October 2024

Motivated by the need for improved platforms in biomedical research, this study addresses challenges associated with traditional Ussing chamber systems, widely used in studying biological barriers like the epithelial barrier of the gut. These challenges include complexity, high sample volumes, and limited compatibility. By combining stereolithography and soft lithography techniques, a microfluidic Ussing chamber is manufactured, overcoming these limitations, and incorporating compatibility with microscopy. Validation through Trans-Epithelial Electrical Resistance (TEER) measurements confirms its efficacy in assessing ion permeability dynamics, utilizing Caco-2 cell monolayers. The study showcases the capability of the manufactured chamber for sensing impact of calcium on tight junctions.
Airy pulse generation in a dispersive injection-seeded frequency-shifting fiber loop
Authors: Cuenca Miguel , Maestre Haroldo , Fernández-Pousa Carlos R.
Published: October 2024

We report the generation of Airy pulses in an injection-seeded, amplified fiber loop incorporating an acousto-optic frequency shifter and a dispersive delay line implemented through a series combination of linearly chirped fiber Bragg gratings. The combined effect of unidirectional frequency shifting and first-order dispersion generates a frequency comb with cubic spectral phase, equivalent in the time domain to a single-sided, bandlimited Airy pulse train. The present approach demonstrates the use of intra-loop phase-only filtering for the generation of tailorable optical waveforms in recirculating fiber loops.
Environmental Monitoring of Submarine Cable in Madeira Island
Authors: Cunha Cristina , Monteiro Catarina , Martins Hugo F. , Silva Susana , Frazão Orlando
Published: October 2024

Distributed acoustic sensing (DAS) is a sensing technique that allows continuous data acquisition of strain rate and temperature with exceptional spatial resolution, up to few meters, for extensive lengths up to 100 km. The ubiquitous nature of optical fiber cables rendered DAS an appealing alternative for geophysical sensing, allowing cost-effective data collection with extensive spatial coverage leveraging existing infrastructure. This study presents findings from the deployment of a DAS system on a dark fiber located on the Madeira Island, Portugal. Through the implementation of 2D filtering, simultaneous analysis of data from road traffic, ocean waves, and seismic activity was achieved.
How to spread optics in an interactive manner – LUZADA (USCOPTICA Student Chapter & Santiago YM Section): Our activities in 2023 & 2024
Authors: Doval Alejandro , Muñoz-Ramos Alicia , Santiago-Alonso Antía , Carnero Bastián , Insua-Costa Damián , Feijoo-Piedrafita Daniel A. , Romo-Díez Irene , Varela-Carballo Javier , Paz-Martín José , Fernández-Rodicio Sabela , Villa-Ortega Verónica , Radziunas-Salinas Yago , Flores-Arias María Teresa
Published: October 2024

Spreading optics and photonics arises as a pivotal duty for researchers in the field, aiming to inspire new generations of students to pursue a scientific career. Furthermore, essential abilities for researchers such as explaining science to an audience or approaching abstract concepts in a visual manner can be easily learnt whilst performing science fostering activities. With these ideas in mind, USCOPTICA Student Chapter and Santiago USC YM Sections were born. Bachelor and Master students and early-stage researchers collaborate in our group, performing diverse outreach sessions, comprising hands-on scientific workshops in schools and science diffusion events, roundtables raising awareness on social issues in Academia and cycles of conferences in collaboration with other student groups. The following abstract aims to share with the scientific community our major activities in the last two years.
In-situ assessment of laser-chemically machined surfaces by means of an indirect optical measurement approach and scanning confocal fluorescence microscopy
Authors: Niehaves Claudia , Bouraoui Yasmine , Radel Tim , Tausendfreund Andreas , Fischer Andreas
Published: October 2024

The manufacturing rate of laser-chemical machining (LCM) is limited to avoid disruptive boiling bubbles in the process fluid. Adjustments to e.g. the laser beam or the fluid properties can increase the removal rate. However, the existing understanding of the surface removal mechanisms is insufficient to ensure the removal quality under these conditions. Thus, near-process measurements of the surface geometry and the surface temperature are required for an improved process modeling. Due to the complex process environment, no suitable in-process measurement technique for the geometry or surface temperature exists so far. This contribution presents an indirect geometry measurement approach based on scanning confocal fluorescence microscopy that is integrated into the LCM plant. As a result, it is shown that the approx. 200 μm deep micro-geometry of laser-chemically processed surfaces can be indirectly measured in-situ, i.e. inside the LCM system. The realized setup is designed in such a way that in future it will be additionally possible to measure the temperature by means of the fluorescence life-time.
In-situ temperature monitorization in oscillatory flow crystallizer using optical fiber sensors with a Bragg grating inscribed at the fiber tips ends
Authors: Soares Liliana , Novais Susana , Ferreira António , Frazão Orlando , Silva Susana
Published: October 2024

Optical fiber sensors were implemented to measure in-situ temperature variations in an oscillatory flow crystallizer operating in continuous. The sensors were fabricated by cleaved in the middle 8 mm-length fiber Bragg gratings, forming tips with a Bragg grating of 4 mm inscribed at the fiber ends. The geometry of the sensors fabricated, with a diameter of 125 μm, allowed the temperature monitorization of the process flow, inside the crystallizer, at four different points: input, two intermediate points, and output. The results revealed that the proposed technology allows to perform an in-situ and in line temperature monitorization, during all the crystallization process, as an alternative to more expensive and complex technology.
Intracellular delivery, imaging and drug-sensing using a plasmonic-enhanced hybrid nanostystem
Authors: Mangini Maria , Cave Donatella Delle , Tramontano Chiara , Corona Marco , De Stefano Luca , Rea Ilaria , De Luca Anna Chiara , Lonardo Enza
Published: October 2024

Metastasis stands as the leading cause of mortality among colorectal cancer (CRC) patients. Galunisertib (LY2157299, LY) is a small molecule demonstrating promising anti-cancer effects by targeting the Transforming Growth Factor-beta (TGF-β) pathway. This route plays a pivotal role in initiating the epithelial-to-mesenchymal transition (EMT), a critical process for metastatic spread. Unfortunately, LY chronic treatment causes undesired effects. To mitigate these side effects, nanoscale drug delivery systems have emerged as a transformative approach in cancer treatment, enhancing drug effectiveness while minimizing toxicity. In this study, we introduce a hybrid nanosystem (DNP-AuNPs-LY@Gel) comprising porous diatomite nanoparticles decorated with plasmonic gold nanoparticles (AuNPs), encapsulating LY within a gelatin shell. This multifunctional nanosystem demonstrates efficient LY delivery, EMT reversal in CRC 2D and 3D cultures, and anti-cancer effects in vivo. Moreover, the nanosystem allowed the quantification with sub-femtogram resolution of the drug intracellularly released using surface-enhanced Raman spectroscopy (SERS). The release of LY is triggered by CRC cell acidic microenviroment. Real-time monitoring of drug release at the single-cell level is achieved by analyzing SERS signals of LY within CRC cells. The heightened efficacy of LY delivery through the DNP-AuNPs-LY@Gel complex offers a promising alternative strategy for reducing drug dosages and subsequent undesired effects.