bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogen bond networks in gas-phase complex anions
Authors: Lai Zhisheng , Shen Minhui , Shen Yong , Ye Yu-Xin , Zhu Fang , Xu Jianqiao , Ouyang Gangfeng
Published: October 2022

Hydrogen bond networks and low barrier hydrogen bonds are demonstrated in the complex anions formed between α-cyclodextrin and benzoic acids.
One pot tandem dehydrogenative cross-coupling of primary and secondary alcohols by ruthenium amido-functionalized 1,2,4-triazole derived N-heterocyclic carbene complexes
Authors: Kumar Anuj , Ta Sabyasachi , Nettem Chandrasekhar , Tanski Joseph M. , Rajaraman Gopalan , Ghosh Prasenjit
Published: October 2022

Three neutral 1,2,4-triazole derived amido-functionalized N-heterocyclic ruthenium carbene complexes efficiently catalyzed one-pot tandem dehydrogenative cross-coupling of primary and secondary alcohols via a metal–ligand non-cooperative pathway.
Corrosion mitigation for steel in acid environment using novel p-phenylenediamine and benzidine coumarin derivatives: synthesis, electrochemical, computational and SRB biological resistivity
Authors: Elaryian Hani M. , Bedair Mahmoud A. , Bedair Ahmed H. , Aboushahba Rabab M. , Fouda Abd El-Aziz S.
Published: October 2022

Three novel p-phenylenediamine and benzidine coumarin derivatives were synthetized (PhODB), (BODB) and (DODB), these compounds showed excellent anti corrosion effect for steel in 1.0 M HCl and significant SRB resistance.
Designing dibenzosilole core based, A2–π–A1–π–D–π–A1–π–A2type donor molecules for promising photovoltaic parameters in organic photovoltaic cells
Authors: Rani Saima , Al-Zaqri Nabil , Iqbal Javed , Akram Sahar Javaid , Boshaala Ahmed , Mehmood Rana Farhat , Saeed Muhammad Umar , Rashid Ehsan Ullah , Khera Rasheed Ahmad
Published: October 2022

Four new molecules from the π–A–π–D–π–A–π type reference molecule “DBS-2PP”, were designed for their potential application in organic solar cells by adding peripheral A2acceptors to the reference.
Supramolecular polyelectrolyte hydrogel based on conjoined double-networks for multifunctional applications
Authors: Yang Wen Jing , Zhang Rui , Guo Xian , Ma Ruixiang , Liu Zhiyuan , Wang Ting , Wang Lianhui
Published: October 2022

A supramolecular polyelectrolyte PVA-PAANa-PAH hydrogel with excellent mechanical properties and superior conductive stability has been fabricated for multifunctional applications.
Thermally robust Al2O3–La3Si6N11:Ce3+ composite phosphor-in-glass (PiG) films for high-power and high-brightness laser-driven lighting
Authors: Huang Min-Hang , Zhu Qiang-Qiang , Li Shuxing , Zhai Yue , Zhang Hong , Wang Le , Xie Rong-Jun
Published: October 2022

Al2O3 particles are introduced into a La3Si6N11:Ce3+ PiG film to form a composite color converter for realizing high-brightness laser lighting.
A Dynamic Adjust‐Head Siamese network for object tracking
Authors: Qiu Shoumeng , Gu Yuzhang , Chen Minghong , Yuan Zeqiang , Yao Zehao , Zhang Xiaolin
Published: October 2022

Siamese network based trackers formulate tracking as a similarity matching problem between a target template and a search region. Virtually all popular Siamese trackers use cross‐correlation to measure the similarity between the deep feature of template and search image. However, the emphasis for feature extraction in different parts of the image are the same. Besides, the global matching between the template and search region also seriously neglects the part‐level information and the deformation of targets during tracking. In this study, to tackle the above issues, a simple but effective Dynamic Adjust‐Head (SiamDAH) model is proposed to extract features from different parts of an object. In addition, an improved pixelwise cross‐correlation model (PWCC) is designed to enhance the naive cross‐correlation operation to produce multiple similarity maps associated with different parts of the target. Experiments on serval challenging benchmarks including OTB‐100, GOT‐10k, LaSOT, and TrackingNet demonstrate that the proposed SiamDAH outperforms many state‐of‐the‐art trackers and achieves leading performance.
GS 121–05–037: A new Galactic chimney candidate with signs of triggered star formation
Authors: Suad L. A. , Molina Lera J. A. , Cichowolski S.
Published: October 2022

Aims. The goal of this study is to analyze the H i supershell GS 121–05–037 and its role in triggering star formation.

Methods. To characterize the supershell, we analyzed the H i 21-cm line and the far-infrared emission distributions. In addition, to study the star formation processes related to GS 121-05-037, we used the Gaia survey, together with spectrophotometric calculations, and derived a method to look for massive OB–type stars.

Results. The H i characterization of GS 121–05–037 shows an expanding structure centered at (l, b) ~ (121°.3, −4°.8) in the velocity range from −47.8 to −25.2km s−1. It is located at 3.2 ± 1.0 kpc from the Sun and has a kinetic energy of Ek = (2.1 ± 1.3) × 1050 erg. GS 121 −05−037 presents, in the H i emission distribution, an open morphology toward the Galactic halo. The analysis of the IR emission reveals the presence of 32 Hii regions seen projected into the borders of GS 121–05–037. A spectrophotometric analysis to look for the ionizing stars of these regions reveals that 12 of them would be located at a similar distance to GS 121–05–037.

Conclusions. The relative location between GS 121–05–037 and the Hii regions, together with their age difference, led us to conclude that the ionizing stars could have been created due to the expansion of the H i supershell. On the other hand, the Hii regions located on the interface of two or more supershells could have originated from the collision of the H i structures. Finally, the open morphology of GS 121 –05–037 toward the halo suggests that this large structure could be a Galactic chimney.
A possible nearby microlensing stellar remnant hiding in Gaia DR3 astrometry
Authors: Jabłońska Maja , Wyrzykowski Łukasz , Rybicki Krzysztof A. , Kruszyńska Katarzyna , Kaczmarek Zofia , Penoyre Zephyr
Published: October 2022

Massive galactic lenses with large Einstein Radii should cause a measurable astrometric microlensing effect, that is, a light centroid shift due to the motion of the two images. Such a shift in the position of a background star due to microlensing was not included in the Gaia astrometric model, and therefore significant deviation should cause Gaia’s astrometric parameters to be determined incorrectly. Here we study one of the photometric microlensing events reported in the Gaia Data Release 3, GaiaDR3-ULENS-001, for which a poor goodness of Gaia fit and erroneous parallax could indicate the presence of an astrometric microlensing signal. Based on the photometric microlensing model, we simulated Gaia astrometric time series with the astrometric microlensing effect added. We find that including microlensing with an angular Einstein radius of θE = 2.60−0.24+0.21 mas (2.47−0.24+0.28 mas) assuming a positive (negative) impact parameter, u0, reproduces the astrometric quantities reported by Gaia well. We estimate the mass of the lens to be 1.00−0.18+0.23 M⊙ (0.70−0.13+0.17  M⊙) and its distance 0.90−0.11+0.14 kpc (0.69−0.09+0.13 kpc), proposing the lens could be a nearby isolated white dwarf.
Integrated optical phased arrays with circular architecture on a silicon platform
Authors: Benedikovic Daniel , Liu Qiankun , Sanchez-Postigo Alejandro , Atieh Ahmad , Smy Tom , Cheben Pavel , Ye Winnie N.
Published: October 2022

Optical phased arrays (OPAs) are now at the forefront of photonic research as a key beam steering technology for myriad of photonic applications, including in light detection and ranging (LIDAR), communications, and metrology, among others. Integrated OPAs with narrow beam widths and wide-angle steering are in critical need, especially for LIDARs in autonomous vehicle, drone and airplane navigation, or satellites. In this work, we numerically study the performances of OPAs having a circular layout arrangement. Compared to recently available solutions with 1D linear or 2D rectangular arrays, the proposed circular OPAs are poised to deliver effective suppression of the grating sidelobes, while improving beam steering range and obtaining narrower beamwidths. We demonstrate 110-element circular arrays with sidelobe suppression better than 10 dB and an angular beamwidth of 0.5°. Under a monochromatic operation at a 1550 nm wavelength, such array provides a solid angle steering range of 0.21π-sr, with a perspective for performance improvement by using large number of OPA elements and operating under broader spectral range.
Hybrid polymer-titania waveguides for highly integrated circuits
Authors: Doughan Isaac , Oyemakinwa Kehinde , Ovaskainen Olli , Roussey Matthieu
Published: October 2022

We present an innovative waveguide based on the hybridization of a titanium dioxide nano-waveguide within a polymer strip. Through simulations and design we demonstrate that the waveguide sustains principally the quasi-TM fundamental mode and that even in tight bends (radius smaller than 2 μm) light remains confined in the titania layer. Such a waveguide, in addition of enabling low loss propagation is a way towards efficient evanescent sensing in highly integrated scheme, i.e., small footprint. We also show that the fabrication, here based on electron beam lithography and atomic layer deposition, can be extended easily to large scale manufacturing using nanoimprinting technology.
III-V compound semiconductor membrane quantum well waveguide lasers emitting at 1 μm
Authors: Richardson Stephen C. , Woods Jonathan R. C. , Daykin Jake , Gorecki Jon , Bek Roman , Klokkou Nicholas T. , Wilkinson James S. , Jetter Michael , Apostolopoulos Vasileios
Published: October 2022

We demonstrate epitaxially grown semiconductor membrane quantum well lasers on a SiO2/Si substrate lasing in a waveguide configuration, for potential uses as coherent light sources compatible with photonic integrated circuits. We study the emission characteristics of In0.13Ga0.87As/GaAs0.94P0.06 quantum well lasers, by using real and reciprocal space imaging. The laser cavity length is 424 μm, it emits light at 1 μm, and lasing thresholds as low as 211 mW were recorded. Control over the position and size of the laser spots by the pump was demonstrated.
Fabrication and optical characterization of erbium-doped silicon diode for quantum communication applications
Authors: Tavani Giulio , Franzò Giorgia , Castriotta Michele , Ferrari Giorgio , Picciariello Francesco , Foletto Giulio , Agnesi Costantino , Villoresi Paolo , Vallone Giuseppe , Rotta Davide , Barri Chiara , Mafakheri Erfan , Celebrano Michele , Finazzi Marco , Bollani Monica , Prati Enrico
Published: October 2022

Quantum Key Distribution allows two users to exchange secret keys and it is based on the transmission of single photons or attenuated laser pulses. Recently, sources based on multiple single-photon emitters were demonstrated to be suitable for QKD. Here, we present a CMOS compatible multiple single-photon emitters source realized on a SOI wafer by a standard silicon diode doped with erbium ions. Particular emphasis is placed on the fabrication of such a device enhancing the erbium electroluminescence signal by adopting a proper oxygen co-doping. Finally, electroluminescence characterization at room temperature of the device is presented.
A brief application of material parameters to predict polishing rates for optical glasses
Authors: Benisch Michael F. , Trum Christian , Bogner O, Werner , Fähnle Oliver
Published: October 2022

This paper investigates the effects of material parameters of optical glasses on the polishing rate of these glasses. For this purpose, the material removal of various glasses was determined in laboratory tests under identical polishing conditions with respect to polishing pad and polishing suspension. The material removal was then evaluated for its dependence on material parameters. The goal of this paper is to derive a rule of thumb which allows an estimation of the material removal and the obtainable surface quality based on certain parameters of the workpiece material under comparable conditions. This rule of thumb can provide an initial insight into the polishability of a material and can be used to estimate polishing times and achievable surface qualities.
Neural Network for Optical Performance Estimation and Advanced Lens Combination
Authors: Brüning Robert , Verhoek Michael , Lippmann Uwe
Published: October 2022

We developed an algorithm to estimate the performance of an optical system based on the errors of its individual components. After a short training period with classical simulated systems, the performance evaluation for tolerancing could be accelerated by a factor of about three million. Additionally, we propose a probability-based sorting algorithm to combine individual, erroneous components in order to compensate for the tolerance budget within the system and increase the overall yield.
Development of a methodology for evaluating the process window of ductile machining for brittle-hard materials
Authors: Fähnle Oliver , Steimer Yannik , Surberg Henrik , Sass Niklas , Buhmann Marco , Liebrich Thomas
Published: October 2022

This paper presents a standardized methodology for determining the process window for ductile machining of brittle materials. Its application for CaF2 is reported, identifying an optimized process window for single-point diamond turning on UPM machines by determining optimized process parameters.
Investigations on a novel process chain for manufacturing of freeform surfaces
Authors: Henkel Sebastian , Schulze Christian , Frank Samson , Letsch Christoph , Bliedtner Jens , Arnold Thomas , Müller Heike , Rädlein Edda
Published: October 2022

Freeform optical surfaces have become increasingly important in recent years, as they can be used to construct optical assemblies with a reduced number of optical surfaces compared to systems without freeform surfaces, and thus optical systems can get more compact and lighter. However, the flexible and efficient production of precise optical freeform surfaces poses a major problem. This manifests itself in insufficient precision of the optics, long delivery times and high prices. It is shown, that ultrasonic grinding processes, combined with an ultra-fine grinding process and subsequent plasma jet polishing, are very well suited for the production of freeform optics and have a high technical and economic potential. Therefore, the aim is to validate an industrially suitable process chain based on this combination, in order to produce freeform optics of high accuracy (shape deviations <100 nm RMS) that can be manufactured in significantly fewer steps than before.
Control of thermal emission for thermophotovoltaic systems
Authors: De Luca Daniela , Caldarelli Antonio , Gaudino Eliana , Farooq Umar , Musto Marilena , Di Gennaro Emiliano , Russo Roberto
Published: October 2022

Thermal emitters play a key role in controlling the thermal radiation emitted in thermophotovoltaic systems and in increasing their energy conversion efficiency. Here, we present different designs of emitters with spectrally selective properties, based on easy-to-fabricate multilayer structures and characterized by a sharp transition from high to low emissivity in the region of interest. Those structures make use of refractory materials to allow working at high operating temperatures and they can be easily customized to maximize the thermal emission in the region of the desired wavelengths.
Mechanical Integration of a Prism-Grating-Prism-Assembly for the CO2M Mission
Authors: Kamm Andreas , Scheffler Christian , Peschel Thomas
Published: October 2022

We developed and realized a mechanical integration concept of a prism-grating-prism-assembly for the CO2M mission. The mechanical design of the mounts relies on a kinematic mounting of the optical elements. Additional, ultra-light and blackened covers for stray light and disturbance light suppression are included. The complete assembly was investigated by extensive thermo-mechanical simulations to verify the stability of the mechanical design under operational, launch loads and test conditions.
Design and testing of a Kirkpatrick-Baez optics variation
Authors: Stieglitz Veronika , Burwitz Vadim , Doehring Thorsten , Hudec Rene , Vitek Stanislav
Published: October 2022

Beside Wolter I X-ray optics, which are used at most in currently operating X-ray space telescopes, there exist also other optical designs and their usability for space observations is still the matter of studies. This article covers preliminary testing results of an optical module which is based on a modified Kirkpatrick-Baez optics. This X-ray optics, consisting of four sub-modules, was assembled in Prague and tested at the PANTER test facility of MPE afterward. The sub-modules use different reflective coatings, in part developed by our research group, on complementary flat mirrors, which approximate the shape of a Kirkpatrick-Baez optical design. In this contribution we summarise the design of the optical modules, the details of applied coating layers, and the X-ray characterisation results at the PANTER test facility
Large Metal Mirrors for Atmospheric Telescopes
Authors: Yu Guoyu , Walker David , Li Hongyu , Shahjalal Abdullah , Walker Trevor
Published: October 2022

We are developing technologies in processing and metrology to fabricate a 1.4-meter aperture, aspherical surface Aluminium prototype mirror for Cherenkov Telescope Array. The aim is to fast process these large aperture mirrors at low cost. The technical development will ensure the high specifications on the surface quality. Different metrology methods including Swinging Arm Profilometry (SAP) and phase measuring deflectomtry (PMD) are being developed. Recent results have shown very promising progress on these developments. We have excellent record in transferring our research results into industry. These cutting-edge technologies will be transferred to our industry partner to explore further developments.
A Systematic View of Microscope Objective Design
Authors: Zhang Yueqian , Gross Herbert
Published: October 2022

The correction of modern microscope objectives is not usually discussed in literature. We have reported a system review and summarized the design principles in a series of papers in 2019 [1-3]. Here we are introducing the systematic view of microscope objective design with an extension of the database till 2021. Furthermore, a systematic synthesis approach aided by AI will also be discussed.
Single-shot 3D endoscopic imaging exploiting a diffuser and neural networks
Authors: Lich Julian , Glosemeyer Tom , Czarske Jürgen , Kuschmierz Robert
Published: October 2022

Lens-based endoscopes offer high lateral resolution, but suffer from rigid imaging properties, such as a fixed focal plane. We present a miniaturized 0.5 mm diameter endoscope in which the objective lens is replaced by an optical diffuser. The intensity information of the object space is scattered and passed to a camera via a coherent fibre bundle. The image is reconstructed by a neural network. The field of view and resolution depend on the object distance. 3D-single-shot imaging up to video rate can be enabled. The approach shows great potential for applications like robust 3D fluorescence imaging.
Physics-informed machine learning for microscopy
Authors: Xypakis Emmanouil , deTurris Valeria , Gala Fabrizio , Ruocco Giancarlo , Leonetti Marco
Published: October 2022

We developed a physics-informed deep neural network architecture able to achieve signal to noise ratio improvements starting from low exposure noisy data. Our model is based on the nature of the photon detection process characterized by a Poisson probability distribution which we included in the training loss function. Our approach surpasses previous algorithms performance for microscopy data, moreover, the generality of the physical concepts employed here, makes it readily exportable to any imaging context.
Numerical investigation of far-field circular dichroism and local chiral response of pseudo-chiral meta-surface with FEM
Authors: Amboli Jayeeta , Demésy Guillaume , Galas Bruno , Bonod Nicolas
Published: October 2022

Circular dichroism spectroscopy is a sensitive and widely applied technique to detect chiral molecules. Recent studies have shown high prospects for plasmonic metasurfaces of pseudo-chiral nano-resonators in enhancing chiral sensitivity. Here we study the far-field circular dichroism for gold U-shaped metasurfaces by calculating Mueller matrix elements with the Finite element method and investigate its response in light of the near field electric energy and optical chiral density.
Tailoring Magnetic Dipole Emission by Broken-Symmetry TiO2 Metasurfaces
Authors: Bashiri Ayesheh , Vaskin Aleksandr , Tanaka Katsuya , Pertsch Thomas , Staude Isabelle
Published: October 2022

Strong magnetic dipole emission is offered by rare earth ions such as trivalent lanthanides, due to selection rule forbidden electric dipole (ED) transitions. This stimulates the study of optical nanostructures, which efficiently tailor magnetic dipole emission. High refractive index all dielectric nanostructures are promising candidates in this regard due to their strong magnetic response and negligible absorption loss in the visible spectral range. Here, we design and experimentally realize a broken-symmetry titanium dioxide (TiO2) metasurface supporting an out-of-plane magnetic dipole (MD) resonance at 590 nm wavelength, corresponding to the MD transition of trivalent Europium ions (Eu3+). A strong photoluminescence (PL) enhancement of the MD transition up to a factor of 15.5 is observed.
Towards harmonic generation enhancement on silicon
Authors: Rodríguez-Suné L. , Scalora M. , Cojocaru C. , Akozbek N. , Vilaseca R. , Trull J.
Published: October 2022

Nowadays, nanostructures are routinely fabricated and integrated in different photonic devices for a variety of purposes and applications. For instance, nonlinear silicon photonics is an area of interest due to its high compatibility with CMOS technology, offering structure sizes down to 10nm at low cost. When the nanoscale is reached, light-matter interactions can display new phenomena, conventional approximations may not always be applicable, and new strategies must be sought in order to study and understand light-matter interactions at the nanoscale. In this work, we report a comparative experimental and theoretical study of second and third harmonic generation from silicon with the aim of explaining the nonlinear optical properties of this material at the nanoscale. We measure second and third harmonic efficiencies as a function of angle of incidence, polarization and pump wavelength. We compare these measurements with numerical simulations based on a microscopic hydrodynamic model which accounts for different possible contributions to the nonlinear polarization. This way, we have the ability to explain properly the SH and TH signals arising from different silicon samples. Once we have this knowledge, we are able to design more complex structures, such as silicon nanowires, where higher conversion efficiencies can be achieved.
Growth and mid-infrared emission properties of "mixed" fluorite-type Er:(Ca,Sr)F2 and Er:(Ba,Sr)F2 crystals
Authors: Basyrova Liza , Loiko Pavel , Benayad Abdelmjid , Brasse Gurvan , Doualan Jean-Louis , Braud Alain , Hideur Ammar , Camy Patrice
Published: October 2022

Fluorite-type 5 at.% Er3+:(M1,M2)F2 (M1 = Ca, Ba; M2 = Sr) crystals were grown by the conventional Bridgman technique and a comparative study of their spectroscopic properties was performed. The vibronic properties of the fluorite-type crystals were studied by Raman spectroscopy. The Er:(M1,M2)F2 crystals exhibited a slightly inhomogeneous broadening of mid-infrared luminescence spectra as compared to the ‘parent’ compound, Er:SrF2. The luminescence lifetimes of the 4I11/2 and 4I13/2 manifolds were measured, e.g., for the Er:(Ca,Sr)F2 crystal, the luminescence lifetimes were estimated to be 8.64 ms and 5.64 ms, respectively, representing a favorable ratio for mid-IR laser operation.
Design and investigation of a low-threshold organic laser diode using mixed-order DFB cavities
Authors: El Droubi Yara , Gaimard Quentin , Solard Jeanne , Chakaroun Mahmoud , Boudrioua Azzedine
Published: October 2022

In this work, we experimentally and theoretically investigate the optical and electrical optimization of an OLED associated to a mixed-order DFB cavity. We, firstly focus on the design and the fabrication of a mixed-order DFB cavity with a high quality factor. We particularly study the impact of the deposition of the organic layers on the topology and the quality factor of the cavity.
Organophosphorus emitters for OLEDs
Authors: Hissler Muriel , Bouit Pierre-Antoine , Tondelier Denis , Geffroy Bernard
Published: October 2022

In this paper, we present the development of OLEDs using organophosphorus derivatives as emitters. In this study, we were able to show that the structural variations carried out on phospholes, phosphinines and phosphepines (functionalization of the phosphorus atom, nature of the substituents) make it possible to modulate the emission wavelengths and, thus, the emission colour of the diodes. Using this concept, we were able to develop TADF and chiral organophosphorus emitters and hybrids emitting at different wavelengths which can be used for the development of OLEDs. The diode structures used are simple and provide high external quantum yields.
Laser micromachining of diamond: A viable photonic and optofluidic platform
Authors: Jedrkiewicz Ottavia , Kuriakose Akhil , Giakoumaki Argyri N. , Coccia Giulio , Bollani Monica , Ramponi Roberta , Eaton Shane M.
Published: October 2022

We describe how the ultrafast laser micromachining technique applied with different writing methods can be used for the creation of various building blocks essential for the realization of a photonic and optofluidic diamond platform. Waveguides, NV centers, conductive wires, microchannels and microholes can be obtained thanks to laser microfabrication with suitable pulse parameters, making use not only of standard Gaussian laser beams but also of non-diffracting Bessel beams, the latter especially in all those cases where single pass high aspect-ratio microstructures or ablated areas are needed.
One-dimensional photonic crystal for polarization-sensitive surface-enhanced spectroscopy
Authors: Mogni Erika , Pellegrini Giovanni , Gil-Rostra Jorge , Yubero Francisco , Simone Giuseppina , Fossati Stefan , Dostálek Jakub , Martinez-Vazquez Rebeca , Osellame Roberto , Celebrano Michele , Finazzi Marco , Biagioni Paolo
Published: October 2022

We realize and experimentally characterize a novel platform for surface-enhanced sensing through Bloch Surface Waves (BSWs). We test a one-dimensional photonic crystal, with a high index inclusion in the top layer, that sustains surfaces modes with, in principle, arbitrary polarization. This is achieved through the coherent superposition of TE and TM dispersion relations of BSWs, which can also provide superchiral fields over a wide spectral range (down to the UV). The resulting platform paves the way to the implementation of polarization-resolved surface-enhanced techniques.
The role of heat treatment in improving photoluminescence and optically stimulated luminescence of HfO2
Authors: de Farias Soares Alvaro , Hatsue Tatumi Sonia , Woda Clemens , Coronato Courrol Lilia
Published: October 2022

HfO2 is a metal oxide from the IV-B family whose properties have been widely applied in electronics and which displays an important blue emission. Despite this fact, few studies have been dedicated to understanding the role of heat treatment on its luminescence properties. Therefore, this study aimed to investigate the Photoluminescence (PL) and Optically Stimulated Luminescence (OSL) of HfO2 powder synthesized by the precipitation method and the influence of calcination on its luminescence. PL spectra results showed a broad emission band at about 2.6 eV, which was related to absorption at 4.1 eV. Green and blue stimulated luminescence spectra depicted emission bands in a similar region, varying between 2.44 up to 2.71 eV. The increase in the heat treatment temperature promoted signal enhancement, which could be associated with higher oxygen vacancy concentrations. OSL dose-response curves for the sample calcined at 1600 °C are linear up to 0.6 Gy and a good signal reproducibility is observed, which makes the material suitable for OSL dosimetry.
Polarized light guiding anisotropic deformation and relaxation in photosensitive polymeric substrates
Authors: Urban David , Hjelme Dag Roar , Descrovi Emiliano
Published: October 2022

Light-responsive polymers offer unique possibilities for anisotropic manipulation of objects on the micron scale. Here we demonstrate the reversible anisotropic stretching of a polymeric surface made out of an azopolymer-elastomer blend, in response to green laser irradiation with varying polarization. We quantify the stretching parameters and the residual strain after relaxation by means of a Fourier-based analysis, which exploits a periodic 2D pattern imprinted onto the surface.
Polycrystalline MoO3 films fabricated by pulsed laser deposition for infrared polarization manipulation
Authors: Ceneda Daniele , Lupo Federico Vittorio , Casaletto Maria Pia , Macaluso Roberto , Centini Marco , Abedini Dereshgi Sina , Aydin Koray , Larciprete Maria Cristina
Published: October 2022

We performed infrared optical characterization of polycrystalline MoO3 films deposited by pulsed laser deposition on fused silica substrates. Several samples have been fabricated using different parameters such as temperature and oxygen pressure. Our analysis shows that under appropriate fabrication conditions it is possible to obtain a dominant α-phase film, with a well-defined, normal to surface (z-axis) orientation. These results are confirmed by reflection spectra performed at 45° incidence angle revealing a strong modulation of the sharp z-phonon Reststrahlen band as a function of the incident field linear polarization.
The comb waveguide: a new tool for strong interaction between atoms and light
Authors: Fayard Nikos , Bouscal Adrien , Berroir Jeremy , Urvoy Alban , Ray Tridib , Mahapatra Sukanya , Kemiche Malik , Levenson Juan-Ariel , Greffet Jean-Jacques , Bencheikh Kamel , Laurat Julien , Sauvan Christophe
Published: October 2022

Coupling quantum emitters and nanostructures, in particular cold atoms and waveguides, has recently raised a large interest due to unprecedented possibilities of engineering light-matter interactions. However, the implementation of these promising concepts has been hampered by various theoretical and experimental issues. In this work, we propose a new type of periodic dielectric waveguide that provides strong interactions between atoms and guided photons with an unusual dispersion. We design an asymmetric comb waveguide that supports a slow mode with a quartic (instead of quadratic) dispersion and an electric field that extends far into the air cladding for an optimal interaction with atoms. We compute the optical trapping potential formed with two guided modes at frequencies detuned from the atomic transition. We show that cold Rubidium atoms can be trapped as close as 100 nm from the structure in a 1.3-mK-deep potential well. For atoms trapped at this position, the emission into guided photons is largely favored, with a beta factor as high as 0.88 and a radiative decay rate into the slow mode 10 times larger than the free-space decay rate.
Paraxial quantum fluids light in hot atomic vapors
Authors: Abuzarli Murad , Aladjidi Tangui , Cherroret Nicolas , Glorieux Quentin
Published: October 2022

Hot atomic vapors are widely used in non-linear and quantum optics due to their large Kerr non-linearity. This non-linearity induces effective photon-photon interactions allowing light to behave as a fluid displaying quantum properties such as superfluidity. In this presentation, I will show that we have full control over the Hamiltonian that drives the system and that we can engineer an analogue simulator with light.
Quantum vacuum excitation of a quasi-normal mode in an analog model of black hole spacetime
Authors: Jacquet Maxime J
Published: October 2022

Vacuum quantum fluctuations near horizons are known to yield correlated emission by the Hawking effect. In this talk, I will explain how a 1 dimensional flow of microcavity polaritons may be engineered to produce an effective curved spacetime with a black hole horizon. I will present numerical computations of correlated emission on this spacetime and show that, in addition to the Hawking effect at the sonic horizon, quantum fluctuations may result in a sizeable stationary excitation of a quasi-normal mode of the field theory. Observable signatures of the excitation of the quasi-normal mode are found in the spatial density fluctuations as well as in the spectrum of Hawking emission. I will explain how the driven-dissipative dynamics of the polariton fluid are key to observing the quantum excitation of the quasi-normal mode. Nonetheless, this observation suggests a general and intrinsic fluctuation-driven mechanism leading to the quantum excitation of quasi-normal modes on black hole spacetimes.
Dynamics of passive modelocking in class-B lasers with saturable absorber
Authors: Prati Franco , Perego Auro , de Valcárcel Germán J
Published: October 2022

We address the problem of passive modelocking in class-B lasers with saturable abosrber taking into account the fast dynamics of both gain and absorption. Our model, which is derived from a delay differential equation model, treats in a rigorous way the definition of the fast and slow times which are typically used in the master equation approach. In that way all the dynamical variables obey exact periodic boundary conditions and this makes the model suitable for analytic and numerical treatment. The model accounts for behaviours different from fundamental modelocking, such as Q-switching modelocking and harmonic modelocking.
Nonlinear pulse routing in plasmonic couplers
Authors: Salgueiro José R. , Ferrando Albert
Published: October 2022

We present a system able to discriminate pulses according to their duration with potential applications in all-optical signal multiplexing. The device is based on a directional coupler with nonlinear cores and metallic claddings with dimensions in a nanometric scale. Simulations are carried out using the FDTD technique for ultrashort pulses of femtosecond order. It is shown that the device is able to separate such pulses respect to a time-width threshold which depends on the total energy of the pulse.
Polarization singularities and optical chirality in dielectric metasurfaces
Authors: Andreani Lucio Claudio , Gerace Dario , Minkov Momchil , Zagaglia Luca , Zanotti Simone
Published: October 2022

We theoretically study the relation between polarization singularities and optical properties in dielectric metasurfaces, or photonic crystal slabs. We focus on nondegenerate photonic bands leading to symmetry-protected Bound States in a Continuum (BICs). First, we discuss how BICs lead to polarization singularities in the far field, whose winding numbers – or topological charges – follows from the symmetry of the lattice. Then, we determine the polarization properties via the Stokes parameters, focusing on the conditions for the occurrence of a nonvanishing circular polarization. Finally, we calculate the optical response in reflection and the degree of circular dichroism. The results shed light on the role of polarization singularities and symmetry in determining the optical chirality.
Demonstration of Cognitive Bias on a Noisy Intermediate-Scale Quantum Processor
Authors: Bovino Fabio Antonio , Comi Alessandro
Published: October 2022

The decision-making process of the individual is analogous to the collapse of a quantum system at the moment of measurement, whereby quantum system we mean the decision-maker, his mental processes and the environmental context that influences him in his choices. Classical probability depends on the lack of information, quantum probability is instead intrinsic to the system to be studied, meaning that the system, consisting of the decision-maker and the context, is in a superposition of states, each with its own amplitude of probability. Only the measurement process (the decision) selects in the decision maker a specific state among those in which he was overlapping. We demonstrated on a Noisy Intermediate –Scale Quantum Processor the model of the “order effect”, one of the most important cognitive bias.
Active tuning of the optical response of field-effect-gated transparent conductive oxides
Authors: Sygletou Maria , Bellingeri Emilio , Canepa Maurizio , Bisio Francesco
Published: October 2022

Transparent Conductive Oxides (TCOs) are a class of materials with high optical transparency and electrical conductivity. This combination makes them extremely appealing for solar cells, optoelectronics and infrared-plasmonics applications. In this work, we report the active tuning of the optical response of aluminium-doped ZnO (AZO) films upon electrical gating within a parallel-plate capacitor configuration. We investigated the electrical-bias-dependent optical response of thin AZO films fabricated by pulsed laser deposition by means of spectroscopic ellipsometry (SE). Calculations based on an exponentially-decaying spatial distribution of injected/depleted charge density in the AZO film are in accordance with experimental observations, allowing the extraction of the Debye length.
Reconstruction of coherence matrix in x-representation using nonclassical Hartmann sensor
Authors: Vitek Marek , Peterek Michal , Koutny Dominik , Paur Martin , Stoklasa Bohumil , Motka Libor , Hradil Zdenek , Rehacek Jaroslav , Sanchez-Soto L. L.
Published: October 2022

We show the coherence properties of a signal can be measured by a Hartmann wavefront sensor in a nonclassical regime. Recasting the detection theory of the classical Hartmann sensor in the sense of quantum tomography enables to measure the coherence function, which is an analogy to the density matrix of mixed quantum states. Two methods were tested for the reconstruction of the coherence matrix from the intensity scan in the nonclassical mode of the Hartmann sensor. The reconstruction was performed in a classic way using the POVM matrix and using data pattern tomography.
Stokes CMOS polarimetry limits studied at non-classical polarisation states
Authors: Roiková Eva , Kunc Štěpán
Published: October 2022

We present the study of the two polarisation state analysers. The first consists of a polarisation camera with a removable QWP, and the second consists of a non-polarisation camera with a rotating QWP and a stationary linear polariser. The theoretical analysis and experiment focus on studying the influence of polarimeter optical components accuracy and errors such as retardation errors, misalignments and extinction ratio on Stokes parameters precision. This research is a cornerstone to understanding polarisation state analysers limits. We examined laser beams with non-classical polarisation distribution, namely the Poincaré beam and the beam with radial polarisation.
Achieving the ultimate optical resolution
Authors: Sánchez-Soto Luis L. , Hradil Zdeněk , Řeháček Jaroslav , Brecht Benjamin , Silberhorn Christine
Published: October 2022

The accurate estimation of the separation between two signals is at the core of many modern technologies. We show new quantum-inspired schemes able to estimate that separation at the quantum limit. The method works in the spatial, temporal, and frequency domains. The question of whether the optical coherence brings any metrological advantage to mode projections is discussed.
Practical limits and opportunities with speckle metrology
Authors: Sjödahl Mikael
Published: October 2022

In this presentation, the role of speckles as a carrier of information in phase-based optical metrology is re-visited. Starting with the fundamental mechanisms for speckle decorrelation it is shown that information about the state of an object is transferred through the modified mutual coherence function and can be detected either through the phase, speckle movement, speckle decorrelation or as a combination. The presentation is focusing on practical scale laws that set the limit for what is possible to achieve with present day technology and is demonstrated with a few examples incorporating measurements of microstructural changes, strain, shape, lenses and other refractive index objects.
Tapered multicore fibers for energy-scalable fiber laser systems
Authors: Aleshire Christopher , Steinkopff Albrecht , Klenke Arno , Jauregui Cesar , Böhme Steffen , Koch Tobias , Kuhn Stefan , Nold Johannes , Haarlammert Nicoletta , Schreiber Thomas , Limpert Jens
Published: October 2022

With active multicore fibers (MCFs), many parallel amplifying waveguides can be densely assembled into a common glass cladding. A tapered fiber geometry applied to MCFs enhances the power and energy scalability of these systems by increasing the doped waveguide volume and reducing peak irradiance while maintaining low output mode order. Recent high-energy experiments have achieved 37 mJ ns-class pulse energies with Yb-doped tapered MCFs, with potential application to a new generation of compact MCF-based coherently-combined laser systems. In this submission, latest experimental results with tapered MCFs and flexible fabrication of taper profiles as a post-draw processing step will be discussed. Numerical analyses of MCF tapers will be presented, using beam propagation method (BPM) and mode-decomposition techniques to study mode coupling and inter-core crosstalk. These simulations are used to guide the tapering of existing fibers and aid the design of future “taper-ready” MCFs.
Operating range of efficient Raman converters based on nanofibers immersed in different liquids
Authors: Bouhadida Maha , Verdier Pierre-Enguerrand , Delaye Philippe , Lebrun Sylvie
Published: October 2022

We present the operating range of Raman wavelength converters based on silica nanofibers immersed in liquids for the design of all fibered wavelength converters. This range is bounded on the lower limit by the pump energy necessary to reach the Raman threshold and on the upper limit by the laser induced breakdown of the nanofiber. These breakdown energies are measured in the ns regime for different liquids (water, ethanol, isopropanol) and for air. We finally define guidelines that open the way to a new family of low-cost compact and efficient all-fibered Raman converters that can be directly inserted in optical fibered networks with very low losses.
Using optical nanofibres to mediate cold atom interactions
Authors: Nic Chormaic Síle
Published: October 2022

We discuss several recent advances related to optical nanofibres in cold atom systems, including two-colour dipole trap optimisation using an in-loop stochastic artificial neural network machine learner, upper bound limitations on Rydberg atom excitation due to localised ion formation, spectral lineshapes arising from the high intensity evanescent fields, and two-photon processes mediated via the evanescent field of the optical nanofibre.
Rydberg atoms in the vicinity of an optical nanofiber
Authors: Stourm Erwan , Lepers Maxence , Robert Jacques , Nic Chormaic Sile , Mølmer Klaus , Brion Étienne
Published: October 2022

Highly excited (so-called Rydberg) atoms are the key ingredient of many quantum information schemes. In this presentation, we shall theoretically investigate how spontaneous emission properties and van der Waals interactions of such atoms are modified in the neighbourhood of an optical nanofiber with respect to the free-space (vacuum) case. This work constitutes a very preliminary step towards the realization of a quantum network based on atomic ensembles linked via optical nanofibers.
High peak/average power picosecond pulsed MOPA system with tapered large mode area double-clad Yb-doped fiber
Authors: Ustimchik V. , Motorin E. , Filippov V.
Published: October 2022

In this paper, a high peak/average power picosecond pulsed master‑oscillator power‑amplifier (MOPA) system utilizing tapered large mode area double-clad fiber (T-DCF) is presented. In a high average power regime, we report a pulsed MOPA laser system with average power up to 613 W at 20 MHz repetition rate with 50 ps pulse duration (613 kW of peak power and 30.6 μJ pulse energy). In high peak power regime, over 3MW of peak power pulses (at seed source bandwidth) at 1 MHz repetition rate (310 μJ pulse energy and 310 W average) was demonstrated. The outstanding properties of T-DCF for amplification of laser signals to high power/energy levels with maintaining the excellent beam quality open a new horizon for advanced laser material processing.
Imprinting characteristics of droplet lenses on liquid-repelling surfaces into light
Authors: Bobkova Valeriia , Otte Eileen , Trinschek Sarah , Denz Cornelia
Published: October 2022

We propose an experimental method that allows the investigation of droplets on liquid-repelling surfaces. The described technique goes beyond the standard imaging approaches and reveals a plethora of spatial droplet information, which is usually unavailable. Liquid droplet lenses shape the transmitted light field of a Gaussian laser beam passing though them, thereby forming refracted three-dimensional (3D) light landscapes. We investigate numerically and experimentally these 3D landscapes which are customized depending on the droplet shape as well as its refractive index, and demonstrate the encoding of droplet information. This approach can also be applied for analyzing droplets showing high-speed dynamics, in order to reveal even minimal shape deviations. The developed technique complements and therefor extend the existing conventional tools for the investigation of the droplets formed on liquid-repelling surfaces.
Microdroplet lasers and their applications
Authors: Humar Matjaž
Published: October 2022

Bio-integrated lasers, that are lasers made of biological and biocompatible materials and implanted into cells and tissues, are gaining interest from the research community. Here we show how whispering gallery mode microlasers and microcavities made of solid beads or droplets can be used for sensing different processes in biological materials including inside cells. By making microcavities of a predefined size they can also be used to encode some information and for cell tracking. Sensing and tracking can be applied to highly scattering tissues.
Design of an all-liquid anamorphic imaging device
Authors: Sauter Daniel , Zhao Pengpeng , Zappe Hans
Published: October 2022

The design of a novel anamorphic optofluidic imaging system based on a pair of liquid lenses whose toroidal surfaces create different optical powers in the symmetry-axes is presented. Using electrowetting-ondieletrics for actuation, a cylindrical fluidic system is actuated by 32 azimuthally-distributed electrodes allowing the definition of non-rotationally-symmetric surface shapes. We present the design and simulation of this optical system and show that an anamorphic ratio of 1.43 at a maximum field of view of 6:82° is attainable.
Characterisation of the stability and long-term evolution of the properties of a 45TW laser operating at 10Hz
Authors: Alejo Aarón , Bembibre Adrián , Peñas Juan , Benlliure José , Martín Lucía , Flores-Arias María Teresa
Published: October 2022

Industrial quality applications of high-power lasers working at high repetition rates, including laserdriven particle acceleration, will require laser systems capable of operating in a stable and prolonged manner. Several factors can affect this stability, including the environment conditions, such as temperature or humidity, and the progressive heating of the optical components involved. Here we report on the evolution of the main laser parameters for a 45TW system operating at 10 Hz, showing that a significant change in the wavefront and direction of propagation, even when the laser energy remains sufficiently constant. These results highlight the importance for future laser systems to integrate closed-loop beam tracking diagnostics that can correct the temporal evolution.