From fluorescence microscopy to nanoscopy : keys to imaging beyond the diffraction limit

In this tutorial, I will detail how the quantum or dielectric confinement of electronic wavefunctions can be exploited to achieve optical resonances at the nanoscale. I will then explain how classical electrodynamic theory can be effectively used to study the coupling between quantum emitters or between dielectric resonators but also between quantum emitters and dielectric resonators in both the weak and strong coupling regimes.

I will discuss how this coupling can be used to design complex nanoscale resonators featuring enhanced optical near fields but also to produce the molecular aggregates used in light-harvesting systems. Furthermore, I will show how the formulation of the Purcell factor can be used to analyze luminescence enhancement effects but also to characterize non-radiative energy transfer between fluorescent molecules, highlighting the applications of these phenomena in sensing and biophysics. I will also detail the stringent experimental conditions required to reach a strong coupling regime between quantum emitters and dielectric resonators at room temperature and show some recent realizations, opening exciting perspectives for quantum technologies operating close to room temperature.

-

Luminescent concentrators are parallelepipeds of luminescent material polished on all sides. The light is confined inside the structure and reaches the edges of the parallelepiped with high power density. The use of LEDs as the pump source provides robustness and cost effectiveness for these new sources that combine power and brightness. The presentation will explain the basic principles of LED pumped luminescent concentrators and describe two types of applications : laser pumping and illumination for imaging.

While acoustic emissions are a method for e. g. the monitoring of bridges or for the assessment of the integrity of tanks, we wanted to investigate them for a further field of application. We tested AEs for the monitoring and assessment of a high-quality finishing process for optical components, the polishing of lenses. This process is - even though - it is of incalculable importance for nearly every optical component still a process which is commonly considered as some kind of black magic. With our research, we want to deliver an insight in this process with interacting mechanical and chemical processes. We want to present a method for the in-situ evaluation of a polishing process.

We use hyperspectral imaging to identify the plastic types constituting mixtures of microplastics directly in water. For the current study we used known microplastics made by milling original pristine plastic sheets and mixed them in water. Using database information and spectral information measured on those pristine plastic we created a decision table enabling the identification. This technique is used under these conditions paving a way towards on-field and in-line measurements.

We report on a stabilized single-frequency Brillouin fiber laser operating at 1.06 µm by means of a passive highly nonlinear fiber ring cavity combined with a phase-locking loop scheme. We show significant linewidth narrowing (below 1-kHz) as well as frequency noise reduction compared to that of the initial pump in our mode-hop free Brillouin fiber laser.

Current 2D windshield head-up displays can lead to driver distractions due to a shift of gaze from the road towards a small area of the windshield. Customizable mixed reality real-time head-up displays can increase safety in transportation due to the holographic road obstacles being aligned with the road scene. Based on accelerated parallel processing algorithms, a 4K spatial light modulator, virtual Gabor lenses and a He-Ne laser, 3D holographic road signs appear within 1.15 seconds in the driver’s gaze on the road.

In this contribution we will discuss the experimental application of 3D chiral metamaterials as high sensitivity biosensors, exploiting circular dichroism in transmission. 3D metamaterials with chiral features can be realized by highly accurate and highly localized bottom-up nanofabrication approach. Large chiroptical effects can be engineered, originating from the single element optical resonances, but collective interactions in arrayed configurations can play a significant role, further enhancing these effects. Capability of biomarker detection in the femtomolar range is demonstrated even in complex biofluid matrix.

As part of EU H2020 I-Seed project, an active laser-induced fluorescence observation system for Unmanned Aerial Vehicle is envisioned to simultaneously measure, geo-locate and range the fluorescence-tagged sensors. In this work, we present lab-scale experimental results of a light-sheet Scheimpflug ranging system employing the excitation laser source of the fluorescence observation setup to compliment the ranging capability of the complete UAV payload.

This work's objective is to study the feasibility of decoupling temperature and strain out of a $\phi$-PA-OFDR readouts. For this purpose, the readouts will be subjected to a study using several Machine Learning algorithms, among them, Neural Networks. The motivation which underlies this target is the current blockage in the widespread use of Fiber Optic Sensors in situations where both strain and temperature change (e.g. composite manufacturing and integration processes), due to the coupled dependence of currently developed sensing methods. Instead of using other types of sensors or even other interrogation methods, the objective of this work is to analyze the available information in order to develop a sensing method capable of providing information about strain and temperature simultaneously

Scintillation, beam wandering, and phase front distortion are the principal impacts of atmospheric turbulence on laser beam propagation. The aperture averaging concept might be used to minimize the effect for the first two, but the third, which is important for high-speed free-space communications, is significantly more challenging. More than ten years ago, the institute of communications and navigation (IKN) of the german aerospace centre (DLR) conducted optical downlink experiments with JAXA's OICETS/Kirari-Japan to study the optical LEO downlink channel and assess the viability of this transmission technology for upcoming applications. The present work will study and give a comparable insight into simulation and experimental results showing a significant relationship elevation dependency for parameters linked to index-of-refraction turbulence.

Shack Hartmann (SH) Wavefront Sensing (WFS) brings many advantages that has made it a standard in optical metrology, but it has long been limited by its resolution compared to other solutions, such as interferometry.

We will present a new approach to the linearized focal plane technique (LIFT), formerly developed by ONERA, which is based on the combination of standard SH technology with phase retrieval algorithms. Applied on all the spots of the SH wavefront sensor microlens array, it provides information on high spatial frequencies, allows to reconstruct more modes for each microlens and results in a 16-fold improvement (4x in each transverse direction) of the sensor spatial resolution!

We will present how we have optimized and validated the LIFT technology for optical metrology. We will share some measurements performed on extremely complex wavefronts. Finally, we will propose an implementation for industrial applications such as manufacturing and will describe some use cases.

Benefiting from the same advantages as SH WFS -such as robustness to vibrations and atmospheric turbulence, or the ability to easily work at any wavelength- the LIFT technology presents very promising perspectives for optical and freeform metrology and can advantageously replace, at lower cost and better usability, Fizeau interferometry.

The scientific community has been exploring new concepts as a result of the usage of optical fibers as absolute measurement sensors. While cross-sensitivity is a common issue with optical fiber sensors, this issue has been mitigated by simultaneous measurement techniques. But when it comes to absolute measurements, these methods have some limitations. The white light interferometer, which offers a superb solution for a range of applications, especially for absolute temperature measurement, is one of the most often used methods for absolute measurements.

This paper proposes a proof of concept for a reflective fiber optic sensor based on multimode interference, designed to measure glucose concentrations in aqueous solutions that mimic the range of glucose concentrations found in human saliva. The sensor is fabricated by splicing a short section of coreless silica fiber into a standard single-mode fiber. By studying the principles of multimode interference and Self-imaging it was developed a sensing head that has a total length of 29.1 mm, approximately equal to the second self-image cycle. This sensing head allowed us to detect low concentrations of glucose (ranging from 0 to 268 mg/dl).

A new approach to detect and analyze transverse acoustic mode resonances (TAMRs), responsible for forward Brillouin scattering in optical fibers, is reported using optical whispering gallery modes (WGMs). TAMRs generate perturbations in the geometry and the dielectric permittivity of the fiber that couples the acoustic and optical resonances. This interaction is exploited to probe opto-excited TAMRs exhibiting an optimal efficiency for detecting low-order TAMRs.

Upconverting particles (UCPs) are building blocks of modern photonics. They cannot be used only as imaging agents but also as contactless sensing units. UCPs have already been used for sensing forces, temperature, mechanical properties, and chemical composition. The sensitivity of the luminescence of UCPs to different external stimulus opens the possibility of using them as multiparametric sensors capable of one-shot description of medium possibilities. However, the use of UCPs for multiparametric sensing is limited because of bias: different external stimuli have an identical impact on the luminescence of UCPs. Bias makes impossible the reliable interpretation of the luminescence generated by UCPs and produces erroneous readouts. Avoiding bias requires the development of new strategies in the analysis of UCPs luminescence when used as sensors. In this work, we demonstrate how a single β-NaYF4: Yb3+, Er3+ UCP within an optical trap can provide unbiased measurements of temperature and viscosity. Decoupling thermal and mechanical measurements is achieved by using the luminescence of coupled states for thermal sensing and the polarization of luminescence for the determination of viscosity. The simultaneous and unbiased temperature/viscosity sensing from a single UCP is demonstrated in a series of proof-of-concept experiments

Applying the inverse-source technique, we have developed an analytical model describing the angular radiation and source-plane spatial-spectral coherence property of white light emitting diodes (LEDs) and demonstrated it experimentally. A corresponding elementary-field representation, which benefits by simplifying the treatment of partially coherent beam shaping and imaging problems, is formulated. Moreover, we identify spectral parts of white LED’s spectrum that follow Wolf’s scaling law of spectral invariance.

This work presents an interrogator system based on an erbium-doped fiber ring cavity for refractive-index measurements. This fiber ring cavity is assisted by a fiber Bragg grating and a phase-shift fiber Bragg grating, both with a similar central emission wavelength to increase the output power levels.

We present a long-range Brillouin optical time domain reflectometer (BOTDR) based on photon

counting technology. We demonstrate experimentally the ability to perform a distributed temperature measurement, by detecting a hot spot in a thermal bath at 100 km, and the possibility to achieve measurement until 120 km with a spatial resolution of 10 m. We use the slope of a fiber Bragg grating (FBG) as a frequency discriminator, to convert count rate variation into a frequency shift. A performance study of our distributed sensor as a function of spatial resolution is also presented.

The aluminum nitride bandgap energy matches that of the salt-water binding energy. Here we study the effect of 405-nm light on the rates of evaporation when solutions are imbibed within a porous ceramic aluminum nitride wick. Sensitive measurements are taken in a self-referencing setup and compared to the light-induced capillary fluid response. Evaporation rates increase with light illumination when the solution is more saline, which indicates charge-transfer characteristics. Our results show consistent trends and potential for photonic environmental applications in salt-water separation processes.

The Terahertz region electromagnetic spectrum offers significant importance for space observations, including the ability to penetrate dust clouds and atmosphere of planets, as well as detect the unique spectral signatures of various molecules and atoms. Thus, terahertz spectrometers are of significant importance in space observations. However, current terahertz spectrometers face several challenges that limit their performance and application. The key problems include low resolution and sensitivity, limited bandwidth, large volume, and complexity. In this paper, we introduce the concept for a compact terahertz spectrometer that incorporates a metasurface. We start by modelling, designing, and fabricating the metasurface sample, aiming to optimize its performance within bandwidth from 1.7 to 2.5 THz. Next, we utilize a Quantum Cascade Laser that operates at 2.1 THz to validate our concept. Finally, we apply the spectrum inversion method to achieve a high resolution with R (f/Δf) 273. Our results showcase the successful demonstration of a compact and high-resolution terahertz spectrometer. Our findings provide a valuable strategy for spectrometer design, which can be widely applied optics field, particularly in space detection.

Rapid, reliable and low cost techniques to fabricate biosensors is a hot topic nowadays. Here, we present a BIO-grating fabricated by means of local, selective denaturing of molecules using UV radiation. A phase-mask is used to generate an interferometric pattern of 1420 nm pitch that, when illuminating a biolayer of BSA molecules lead to its periodic deactivation. After the biorecognition of the specific antibody, aBSA, a BIO-grating is generated due to the height difference between the protein, and the complex protein + antibody. We present the optimization of the fabrication of the BIO- gratings and their AFM characterization. Also, the biosensor performance in terms of limit of detection and limit of quantification will be presented.

The development or the improvement of production processes are necessary aspects, in order to enhance the quality and efficiency in optical manufacturing. This paper presents an approach to manufacture fine grinding tools in a very flexible and efficient way. A new filament composed of polyamide, ZrO2 particles and diamond grains is developed and used in an additive manufacturing process for tool fabrication. The resulting tools are successfully applied in an ultra-fine grinding process on fused silica samples.

We report experimental results of a frequency shifted digital holography setup for spatially resolved vibrometry. A spatially homogeneous artificial phase modulation is used as a reference to correct for speckle noise. Furthermore, when superimposed upon the object vibration with slightly different frequency, the resulting beat can be evaluated. The beat frequency is invariant under relative motion between the object and interferometer, providing robustness in presence of parasitic low frequency vibrations. In addition, the ‘working point’ is raised out of the noise floor, providing the opportunity to enhance the sensitivity at small vibration displacements. The method is demonstrated by measurements on a vibrating clarinet reed.

Long-chain hydrocarbons, petroleum and diesel, have long been used as source of energy for locomotives. Unlike it’s short-chain counterpart petroleum, diesel fuel is considered dirtier due to black soot particulates it emits that poses greater health hazard. Here, we attempt to measure the absorbance spectra of premium diesel fuels, neat and adulterated, using terahertz (THz) frequency domain spectroscopy to determine the level of impurities that can further exacerbate its emission. Two broad absorption peaks at 6.42 THz and 7.75 THz as well as narrow peaks at 13.07 THz, 13.88 THz, and in the range of 16-17 THz, characterized the premium diesel. These spectral features are well identifiable in the adulterated samples but their intensities vary depending on the type of impurities. Decrease in the absorbance is observed with water contaminant, increase in isopropanol, while sulfur and methanol contaminants did not influence the absorbance spectra. This technique demonstrates initial but promising results in probing adulteration in petrochemical products.

Stable isotopic compositions of carbon and oxygen (δ13C et δ18O) measured from carbonates are used in geology to reconstruct paleotemperatures and to learn about the evolution of the biogeochemical carbon cycle. The standard technique used since the middle of the XXth century to measure isotopic ratios is based on a wet chemical protocol which CO2 is evolved from the acidic dissolution of carbonates followed by quantification of CO2 molecules isotopologues using mass spectrometer or infrared spectroscopy. This is a lengthy protocol that necessitate to manipulate acid solution and numerous gas phases purification steps before isotopic measurements. Our new preparation technique aims at offering an alternative to the wet chemical preparation of the samples by using a direct extraction of CO2 via a laser-induced calcination process. In addition to save time, this method allows to consider spatially resolved and automated in-situ measurements and does not necessitate further purification steps of the evolved CO2 during calcination.

Achieving efficient mixing of fluids is a great challenge in microfluidics that has been addressed using microstructures. In this work, Stereolithography (SLA) and Pulsed Laser Ablation (PLA) were combined to manufacture a straight micromixer for uniform mixing of fluids. Computational Fluid Dynamics (CFD) simulation was performed to test the device. The results suggest that the combination of these optical technologies can be an effective method for fabricating microfluidic devices with great mixing capabilities.

A new concept for synchro-speed polishing of flat and spherical surfaces is introduced: 3D printed gradient index (GRIN) polishing tools. By using additive manufacturing technologies in combination with photopolymer plastics, GRIN tools can be fabricated that are individually adapted to the workpiece geometry. By using two different plastics, the hardness and therefore the removal rate of certain tool areas can be defined. Surface structures, benefiting material removal rate and tool wear rate, are possible as well as lightweight structures with high mechanically stability. Tools can be fabricated as thin foils as well as solid pads, ranging from small (few mm) to large diameters. Additionally, the pads can be fabricated with an individual radius. This can enable the replacement of radius-dependent tool holders, because the pads can be mounted on flat tool interfaces, since the radius is not dependent from the tool body anymore. First results from the experimental setup are showing, that by using GRIN foils similar surface quality results can be achieved in comparison to conventional polyurethane foils, while the GRIN foils are offering a lot more possibilities regarding process optimization.

We measure the modal dispersion occurring in a single multimode fibre and account for this using a digital micromirror device to form a raster scanning spot in the far field of the distal facet of the fibre. We perform this with a q-switched 700~ps pulsed laser at a 532~nm wavelength. The raster scanning allows us to spatially interrogate the reflectivity of a scene while the time of flight of the pulse gives distance information allowing for the generation of a three-dimensional image.

This study presents an initiative aimed at developing a real-time optical measurement system for non-contact measurement of fungal spores in protected crops such as strawberries, tomatoes, and cucumbers. The measurement system is based on a modified microscope combined with automatic spore trapping and air sampling. The system has been used in field trials. Work is ongoing to develop image-processing and YOLO-based object classification network algorithms to identify and classify fungal spores in high-resolution microscope images in the presence of pollen, dust, and other aerosols.

Albedo plays a vital role in urban microclimates. Civil engineering structures usually absorb a high amount of energy in form of heat, for example asphalt pavements, which have a low albedo, thus contributing to the Urban Heat Island (UHI) effects. Modifying the physical characteristics of asphalt pavements, including reflectance and thermal properties, can help mitigate UHI. The literature points out that one alternative to thermoregulating asphalt materials is the incorporation of phase change materials. Thus, the main goal of this research is to present a systematic review regarding the effectiveness of the incorporation of polyethylene glycol (PEG) 1000, 2000 and 4000 as Phase Change Material (PCM) in asphalt materials. The results showed that incorporating PEG into asphalt materials can regulate heat storage, promoting stability and reducing UHI effects. PEG2000 was more frequently used. PEGs can reduce between of 3.5 and 4.2ºC of the asphalt materials when compared to the conventional ones.

Industrial processes such as smelting and sintering require stable and precise temperature control of furnaces. To achieve this, accurate temperature measurements are required. Pyrometry allows for contactless measurement of bulk materials and is particularly suitable for high temperature applications. One of the main influences on the accuracy of pyrometric measurements is the knowledge of the emissivity in the spectral measurement range. To reduce this dependence, two-color pyrometers or multi-color pyrometers can be used. With this in mind, the IRS is further developing their existing pyrometer technology by designing an advanced multi-channel pyrometer for bulk oven processes in a joint venture with Stange Elektronik GmbH and New Generation Kilns Grün GmbH. The design process is explained here and the different methods of achieving emissivity independence are examined.

The presented investigations build on the results already presented at EOSAM 2022 on the in-situ monitoring of grinding processes, in which high correlations between vibrometry, force and topography data of machined fused silica samples could already be proven. With the help of new measurement setups, it was possible to also detect high-frequency vibration components in CNC grinding processes and to check their effects on the resulting surface qualities. The investigations were carried out on a 5-axis CNC machine and monitored with the help of vibrometric and white-light interferometric measurement technology. The aim was to look at the influences of process-side parameters on the process vibrations and the resulting surface qualities.

Choice of lenses materials in optical design is crucial to reduce aberrations down to an acceptable level. Commercial glasses do not cover a continuous range of refractive indices and must be selected in a discrete library making them discrete variables in any optimization design process to achieve the final optical design to be manufactured. This paper proposes an alternative method to avoid the complicated discrete variables optimization process thanks to a two-steps continuous optimization methodology starting with fictitious glasses models before jumping to the real glasses optimization design. The illustration of this process and achieved results are presented on an example of optical system which validates our proposed method.

Smart lighting systems are capable of producing light when and where it is needed. Such functionality can be achieved with adaptive optical systems, which consist of one or multiple adjustable components, enabling illumination with a variable radiation pattern. This paper introduces the design of a compact, tunable optical system, allowing illumination with variable beam size and beam direction. We demonstrate how this system can be combined with computer vision and a feedback loop, to achieve a fully autonomous, smart illumination system.

High Optoelectronic Chromatic Dispersion in Ge PN-photodetectors is incorporated in an Optoelectronic Oscillator to achieve high sensitivity wavelength monitoring and strain sensing. The sensitivity is enhanced for higher oscillating mode numbers and lower cavity lengths.

The response of three of the most used commercial polymers (poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET) and polypropylene (PP)) with different thermal properties under irradiation with high frequency (1 kHz-1 MHz) femtosecond (450 fs) multi-pulse (N=10-1500) laser at λ=515 (1.34 J/cm2) and 1030 (1.70 J/cm2) is reported. Thermal and ablative effects are observed after laser irradiations. The results are compared to a photothermal model that pretends to explain the heat accumulation effect of successive pulses irradiation. Thermal analyses (Modulated Differential Scanning Calorimetry (MDSC) and Thermogravimetry (TG)) are performed and utilized to explain the different behaviour of each polymer. Three different regimes (non thermal, thermal and saturation) are identified and explained from the model and experimental results. A connection between ablation depth and simulated reached temperature is established. Further studies as micro-Raman analyses on the irradiated area and the dependence of damaged area on the repetition rate are being performed.

Hybrid organic-inorganic perovskites (HOIPs) with Cr3+ ions could be very useful in luminescence thermometry, especially in self-calibrating temperature sensing in a wide temperature range (10-400 K). The upcoming presentation will delve into the structural and optical characteristics of formate hybrid perovskites that incorporate Cr3+ ions. The primary focus will be on examining how the organic cation A+ affects the luminescent properties and temperature sensing capabilities of [A]B(HCOO)3:Cr3+ compounds. Additionally, the presentation will showcase the impact of substituting metal B on the structure, bond lengths, distortions of CrO6 octahedra, crystal field strength surrounding Cr3+ ions, and subsequently, the luminescence properties and temperature detection.

Conducting polymer nanoantennas enable active control of light-matter interactions at the nanoscale and are emerging as a new class of materials for dynamic plasmonics. While metal plasmonics is limited to static function due to fixed permittivity, we demonstrated for the first time that conducting polymer nanostructures can provide tunable plasmonic responses in the near infrared and infrared spectral ranges. Conducting polymer nanodisks of PEDOT:sulf could be modulated by chemical redox reactions[1] as well as by electrical tuning using a convenient ion gel device structure[2]. Furthermore, we showed that semiconducting polymer nanodisks made from PBTTT could provide reversible metal-to-dielectric transition by chemical doping/dedoping and thermal annealing[3]. I will present these studies and discuss our recent further developments within this new research direction of dynamic polymer nanooptics. The emergence of tunable polymer nanoantennas for dynamic plasmonics can be greatly expected for applications in advanced integrated optics, like dynamic holography and virtual reality.

Two-dimensional (2D) Transition Metal Dichalcogenide semiconductors (TMDs) are a promising platform in view of developing a novel generation of optoelectronics devices and renewable photon to energy conversion technologies. However new ultra-compact photon harvesting schemes are required to mitigate their poor photon absorption properties. In this work we propose a novel flat-optic solution where a few layers MoS2 film is conformally deposited on a large area (cm2) nanogrooved template. The subwavelength reshaping of the TMDs film induces the excitation of photonic Rayleigh Anomalies (RA). The latter promote a strong in-plane electromagnetic confinement and can be easily tuned over a broadband spectrum by tailoring the illumination conditions. As a demonstration of the potential of this large-area surface functionalization we employed the hybrid 2D nanopatterns as a photocatalyst in a prototype photobleaching reaction of Methylene Blue (MB) molecules. We demonstrate a strong enhancement of the photochemical MB degradation, well above a factor 2, by effectively tuning the RA mode in resonance to the molecular absorption band. Therefore, these findings pave the way to flat-optics photon harvesting schemes for boosting photoconversion efficiency in large-scale hybrid 2D-TMD/polymer layers, with a strong impact in applications ranging from waste-water remediation to new-generation photonics and renewable energy storage.

Fiber-based sensors have become a promising platform for the development of remote sensing solutions, allowing in-situ and faster responses. These devices are continuously evolving and new methods of improving their performance are constantly being developed, such as the use of chemosensor agent to generate or enhance the signal to be detected. In this sense, lanthanide metal-organic framework (Ln-MOFs) has shown great potential for sensing several analytes, such as gases and volatile organic compounds (VOCs). This work aims to develop sensors based on optical fibers coated with luminescent Ln-MOFs for remote sensing. Oxide glasses were used as a substrate for the in-situ growth of Ln-MOFs synthesized from EuCl3 and carboxylate ligands, specifically trimesic (1,3,5-benzene tricarboxylic) and pyromellitic (1,2,4,5-benzene tetracarboxylic) acids. The Ln-MOFs were deposited on glass bulks and optical fibers and had its structural and photoluminescent properties investigated. The composites were exposed to different organic analytes and photoluminescence measurements revealed a luminescence quenching in the presence of acetone. Thus, such composites seem promising for VOCs sensors, and remote sensing tests can be performed using optical fibers.

Mid-Infrared methane (CH4) spectroscopy results were obtained in band III beyond 7 µm. To achieve this, the generation of supercontinuum covering the spectral range between 5 and 12 µm was realized by using purified chalcogenide optical fibers free of highly toxic elements such as arsenic and antimony. Besides a pumping with an optical parametric amplifier, an all fibered pumping scheme has also been investigated. In both configuration, supercontinuum absorption spectroscopy experiments have allowed for CH4 sensing, concentration as low as 14 ppm has been detected.

Feedback systems have been utilized to reduce the possible thermal side effects of lasers for surgery by means of temperature monitoring to control irrigation systems. In this study, we investigated the potential application of optical coherence tomography as a means of detecting bone dehydration status. We investigated the penetration depth of the OCT laser and its respective relation to the hydration status of bone. A deep-learning method was utilized to differentiate between different levels of water content in bone tissue (fresh/hydrated, dehydrated, and carbonized) based on the OCT images. The proposed model achieved an accuracy of 0.912 on an independent test set, demonstrating its ability to accurately predict the state of the bone considering these three conditions. We believe this method can potentially accelerate the detection of dehydration during laser surgery, improving the safety of using lasers with real-time feedback.

Photoemission in modern high-brightness electron sources is under study at the DESY-PITZ photo injector. The electron source optimization process is under continuous upgrading. The developments in modern digital signal processing provide an opportunity for building intelligent algorithms that implement mathematical methods unattainable by analogue technology which can support the related image of emittance measurements from PITZ system. In this work, we provide an intriguing technique for designing multilayer FIR filters with minimal computing effort. As a result, the filter design is particularly effective at reducing complicated noise and performs quickly and efficiently.

Selective Emitters (SEs) are the main components of solar thermophotovoltaic (STPV) systems; they act as intermediate thermal radiation emitters to shape the incident solar spectrum to match the wavelengths useful for the PV cell. In this work, we present the design, optimisation, fabrication, and characterisation of an SE based on a multilayer design made of SiNx, SiO2, and TiO2 layers. The SE is optimised to work with PV cells based on III-V semiconductors, such as GaSb, InGaAs, and InGaAsS, the bests suitable for SPTV applications. The fabricated SE shows an emitter efficiency (ηSE) of 50% if matched with a PV cell with an energy bandgap of 0.63 eV.

In this work, we present proof of concept of a Raman based distributed temperature sensor using standard telecommunication fiber as the sensing element. To allow coexistence with data transmission, a pump source with a wavelength of 1064 nm is used. The proposed DTS is characterized in the range of 20 °C to 100 °C, using the ratio between the Raman band’s powers linearized. We established a characteristic curve of the sensor with a sensitivity of 0.0018±0.0001 /°C, showing that the proposed DTS can detect temperature variations. This work is the first step forward in the development of distributed sensors that coexist with data transmission over the same optical fiber.

Recent results of a long-term effort of Tomsk-Reims research teams on accurate intensity data obtained from high-resolution absorption spectra of ozone suitable for the atmospheric remote sensing in a wide IR range are summarized. This includes vibronic bands corresponding to the transitions towards triplet electronic states near 1 micron, and vibration-rotation bands covering the far-infrared and near-infrared ranges.