Error message

Warning: mysqli_connect(): Headers and client library minor version mismatch. Headers:50552 Library:50634 in eval() (line 52 of /data/cetal/modules/php/php.module(80) : eval()'d code).


4 iulie 2017 - Ziua LaMP
9:00 - 9:30
Author: Marian ZAMFIRESCU
Abstract: The CETAL infrastructure will be presented. The access rules at CETAL (RAIC), will be explained. Statistics regarding the last years activities, access applications, financing and human resources will be discussed.
9:30 - 9:45
Title: Prezentarea Laboratorului de Procesari Laser din INFLPR CETAL
Author: Irina Paun
Abstract: Laser Material Processing Laboratory supports fundamental research and industrial applications in the field of laser materials processing. We focus on laser processing of various materials (polymers, glasses, ceramics, metals, composites) at macro-, micro- and nanometer scale.Our research results emerge in cutting edge technologies for the industrial sector.
9:45 - 10:00
Title: Laser direct writing of stimuli responsive biomimetic structures for bone renereration
Author: Irina Paun
Abstract: A major concern in orthopedic implants is to decrease the chronic inflammation using specific drug therapies. The newest strategies rely on the controlled delivery of antiinflammatory drugs from carrier biointerfaces designed in the shape of 3D architectures. We report on electrically responsive microreservoires (ERRs) acting as microcontainers for antiinflammatory drugs, as potential biointerfaces in orthopedic implants. The ERRs consist in arrays of vertical microtubes produced by laser direct writing using two photon polymerization effects (2PP_LDW) of a commercially available photoresist, IP-L780. A polypyrrole (conductive)/dexamethasone (drug model) (PPy/Dex) mixture was loaded into the ERRs via a simple immersion process. Then, the ERRs were sealed with a poly(lactic-co-glycolic acid)(PLGA) layer by Matrix Assisted Pulsed Laser Evaporation. ERRs stimulation using voltage cycles between -1V and + 1V, applied at specific time intervals, at a scan rate of 0.1 Vs-1, enabled to control the Dex release. The release time scales were between 150 and 275 hours, while the concentrations of Dex released were between 450-460nM after three applied voltage cycles, for different microreservoires dimensions. The proposed approach was validated in osteoblast-like MG-63 cell cultures. Cell viability and adhesion assays showed that the Dex-loaded ERRs sustained the cells growth and preserved their characteristic polygonal shape. Importantly, for the electrically-stimulated Dex release, the level of the alkaline phosphatase activity increased twice and the relative level of osteocalcin gene expression was 2.2 times higher as compared with the unstimulated drug release. Overall, the ERRs were able to accelerate the cells osteogenic differentiation via electrically controlled release of Dex.
10:00 - 10:15
Title: Investigation of dissimilar laser welding in lap joint configuration
Author: Diana Chioibasu
Abstract: Laser welding technique, using a continuous wave (CW) fiber laser with 400 W of maximum power, was applied in lap joint configuration to weld 1 mm thick stainless steel (SS 316L) to 1 mm thick aluminium (A 1050) with the stainless steel on the top. The laser was used at maximum power for ensuring full penetration depth and further on, laser process parameters, like laser velocity and focusing position, were optimized in order to produce pore free and aesthetic welds. The dissimilar joints were studied by optical metallography and scanning electron microscopy (SEM) and mechanically evaluated by pull-out tests. Based on the analyses results, the potential of this joining method will be discussed
10:15 - 10:45
Title: Elemente optice difractive fabricate prin tehnici de scriere directa cu laserul
Author: Bogdan Ştefăniţă CĂLIN
Abstract: Această lucrare este centrată pe studiul elementelor optice difractive (DOE = (eng.) “Diffractive optical element”) ce eprezintă o clasă de dispozitive optice active şi pasive utilizate pentru a obţine distribuţii arbitrare de intensitate. O categorie specială de DOE este reprezentată de acele elemente ce modulează lumina incidentă sub forma calculată într-o hologramă generată pe calculator (CGH). Scopul central al acestei lucrări constă în parcurgerea unui ciclu proiectare-realizare-caracterizare în urma căruia să rezulte un DOE configurat corespunzător pentru a avea funcţionalitatea unei holograme (DOE-CGH). Vor fi discutate elemente de proiectare, 3 tipuri de DOE realizate in laboratorul LaMP (Laser Material Processing Laboratory), si rezultate experimentale in cazul DOE pentru generare de imagini arbitrare, precum si pentru generare de fascicule Airy bidimensionale.
11:15 - 11:30
Title: Synthesis of graphene oxide / transition metal oxide / noble metal hybrid nanocomposites for environmental applications
Author: Angela Datcu
Abstract: Reduced graphene oxide is intensively investigated because of its high conductivity, excellent electron mobility, and high surface area. Due to these outstanding properties, graphene oxide based materials are of interest for a wide range of practical applications as electronics, photocatalysis, energy storage/conversion, biomedicine etc. We prepared reduced graphene oxide/transition metal oxide/noble metal nanocomposite thin films through matrix assisted pulsed laser evaporation (MAPLE) technique. The chemical composition of the thin films was controlled by the ambient gas nature (argon, oxygen or nitrogen) and pressure in the MAPLE irradiation chamber. We used a frequency quadrupled Nd:YAG laser source for the irradiation of the MAPLE targets. The graphene oxide reduction and nitrogen doping processes were extensively investigated. The photocatalytic activity of the hybrid nanocomposite films has been analyzed through the degradation of organic dye solutions under either UV or Vis light irradiation conditions. The photocatalytic efficiency of the nanocomposite films was significantly higher as compared to convenitonal pure transition metal oxidecatalysts. Keywords: graphene oxide; transition metal oxide; photocatalysis; laser based techniques; thin films
11:30 - 11:45
Title: Obținerea și caracterizarea substraturilor SERS
Author: Catalin Luculescu
Abstract: Obtinerea si caracterizarea de substraturi SERS functionale in INFLPR.
11:45 - 12:00
Title: In situ nanoparticle production for biomedical appliations
Author: Aurelian Marcu
Abstract: Iron oxide nanoparticles are having various industrial and bio-medical applications. However, for biological applications, hematite (Gamma Fe2O3) nanoparticles present the big advantage of a high biocompatibility combined with magnetic properties. In-situ production of magnetic iron oxide nanoparticles is demonstrated using ultrashort laser pulses ablation in liquids. Thermal effects associated with other laser ablations techniques are avoided due to the pulse duration much beyond 1 which ps not sufficient to trigger the thermal effect. Thus, the material is ablated by nonlinear effects (as multi-photon absorption) producing nanometric structures expelled from the target. The nanoparticles resulted from few laser parameters were analyzed using dynamic light scattering DLS method to extract information about sizes distribution and electric charge potential. Preliminary biological invetigations on nanoparticles biocompativility were also performed. Thus, some results on nanoparticle charge and size are presented, while the preliminary biological investigations were only suggesting a good biocompatibility but a need of using functionalization techniques for these particles application in farmacophor transport application.
12:00 - 12:15
Title: Laser emission from Nd doped waveguides realized by direct fs- laser writing technique
Author: Gabriela CROITORU
Abstract: The ability of a femtosecond- (fs-) laser beam to induce changes of the refractive index in amorphous or crystalline media provides a suitable technique and is recognized today as a powerful tool for realizing waveguide lasers. Various waveguide configurations have been inscribed in many laser active media, such as: double- line and depressed cladding waveguides of different shapes (circular, elliptical or rectangular). In this work we present our recent results regarding realization of waveguide lasers in Nd:YAG and Nd:YVO4 by the direct fs-laser beam writing method, and on emission at 1.06 and 1.3 microns from these waveguides using the pump with a fiber-coupled diode laser. In the first experiments we used a step-by-step translation technique to inscribe two-wall type and cladding waveguides with various shapes (circular, elliptical and rectangular) in Nd:YAG, Nd:YVO4 single crystals and Nd:YAG ceramic media. We measured the waveguides propagation losses. The laser emission was obtained using the pump at 807 nm with a fiber-coupled diode laser for Nd:YAG media and the pump at 809 nm for the Nd:YVO4 crystals. We have also developed a new method of writing circular waveguides by moving the laser medium on a helical trajectory during the inscribing process, the medium direction of translation and the fs-laser beam being parallel. Circular waveguides with well- defined walls and low propagation losses were realized in a 1.1-at.% Nd:YAG ceramic, and efficient laser emission was obtained. This kind of devices shows good potential for realization of compact, efficient laser sources for optoelectronics.
12:15 - 12:30
Title: 2D Photonic Crystals using laser beam nano-patterning on very thin films MS deposited
Author: Bogdan Alexandru Sava
Abstract: A new coating technology will be developed able to build new nano-multifunctional periodic structures for the most sophisticated laser mirrors up to Photonic crystals/PC. The main target is a new thin films technology/tuned surface for energy-efficient approaches. Two spatial dimensions photonic crystal/2D-PC particularly designed as light intensifier will be nano-structured in periodic 2D-geometry using laser beam nano-patterning for a resolution better than 150 nm. 2D-PC inside the active surface represents a complex nano-resonant cavity which will be tuned on visible frequencies of the spectral wavelengths.
12:30 - 12:45
Title: Yielding multifunctionality of laser processed thin films/nanostructures through chemical pressure and epitaxial strain
Abstract: Perovskite, lead-free materials have become very attractive lately for a broad range of applications such as photovoltaic, photocatalytic, electronics and so on. Exhibiting a wide range of functional properties, ranging from normal ferroelectrics up to relaxor ferroelectrics by varying the amount of A-site and/or B-site substitutions in the perovskite systems, bulk lead free perovskites are intensively studied. Nonetheless, to transpose bulk properties to thin films is a major achievement. In this work, I will underline how critically important materials for eco-friendly (Pb-free) multiferroic multifunctional devices can be tailored, by joining doping and epitaxial strain engineering to create a nanoscale stripe structure, in order to overcome major intrinsic material's drawbacks.
12:45 - 13:00
Poster presentation
Title: SnO2- ZnO Thin Films Gas Sensors for CO Detection
Author: Andreea Mihailescu
Abstract: Thin films of SnO2 mixed with ZnO, in a weight ratio of 3 to 1 were grown by pulsed laser deposition (PLD) on glass substrates, at 10Pa and 50Pa pressures, respectively, in a reactive O2 atmosphere. Microscopy investigations such as SEM and AFM, together with XRD revealed a high degree of roughness and a polycrystalline state of the oxide films. The gas sensing properties of these films were tested at different concentrations of CO in nitrogen by measuring their electrical sheet resistance and were found to be highly sensitive to concentrations as low as 1ppm, with an optimum operating temperature of 400C. Reduced concentrations of CO were detected even at 300C, with satisfactory response and recovery times. Pt interdigitated electrodes were deposited on the top of coatings by means of a mask fabricated in CETAL using the TruLaser Cell 3010 machine.
5 iulie 2017 - Ziua PW
9:00 - 9:15
Title: Prezentarea laboratorului CETAL-PW
Author: Mihai Serbanescu
Abstract: The CETAL-PW laboratory infrastructure will be presented with actual status, challenges, results and future projects.
9:15 - 9:30
Title: Control and sincronization system for CETAL-PW laser
Author: Mihai Serbanescu
Abstract: CETAL laser facility is one of the most important high power (Pettawatt class) laser open user facility in South-Est of Europe. The laser system shell deliver 1PW peak power and is fully based on the Ti:Sapphire technology. The pettawat laser system consist a front-end and multi pass laser amplifier and is built in modular configuration. This laser system allows two regime of operation: first regime is capable to deliver a peak power of 1PW at 0.1 Hz repetition rate and the second regime is 45 TW at 10 Hz. Both of those regime of operation are delivering the pulses into the interaction chamber placed inside radiation shielding underground bunker. The initial control configuration of this laser (for 10 Hz and 0.1 Hz operation) regime was made in “continuous mode” in delivering pulses and associated synchronization electrical signals. An in-house customized synchronization system was implemented to the laser system to work in order to extend the delay generation unit capabilities over shot to shot and burst modes of delivering pulses and synchronization signal to experimental area. In this work the entire schematic solution is detailed described.
9:30 - 9:45
Title: Beamlines Control and Automation at CETAL-PW Laser Facility
Author: Alexandru Achim
Abstract: The CETAL-INFLPR laser facility ( aims to runs at 45 TW with 10 Hz repetition rate and at 1 PW with repetition rate of 0.1 Hz, delivering pulses with about 25 fs pulse durations with beam size of 200 mm full aperture and 160 mm FWHM. While the laser beam spatio-temporal properties can be well adjusted through the amplification chains of ultra-intense laser systems, the major issues are related to the beam delivery on target, to both spatial and temporal pulse structure affected by complexity of the beam transport system. From optical compressor the laser beam is traveling under vacuum (10-6 mbar) and the inner diameters pipes are 250 mm which is quite close with beam size. To prevent eventually clipping beam wall pipe a monitoring of laser beam and a active alignment system is necessary. Several works which address this issue where performed by different other research group. For laser optimization in optical accelerator automatic laser tuning relying on metaheuristic algorithm were used for optimizing spatial (transverse) and temporal laser profile. In order to make a fully automation system of optical elements a set of CCD cameras , motorized mirror stages, window shutters and motor controllers will be inserted. The signal from all devices will be processed to a central server which will hold and monitor all devices. The present paper describe a semi-automated alignment system based on dedicated control software and CCD cameras in the closed loop with the motorized mounts which will overcame the all issues addressed.
9:45 - 10:00
Title: Sincronizarea pulsurilor laser ultra-scurte ce provin de la doua amplificatoare dispuse in paralel
Author: Sandel Simion
Abstract: Lucrarea prezinta munca de cercetare / dezvoltare a unei metode si prototip de sincronizare la tinta a pulsurilor laser ce provin de la doua amplificatoare multipas (avand sursa comuna a pulsurilor de amplificat). Scopul acestei sincronizari este realizarea combinarii coerente si necoerente a pulsurilor laser furnizate de catre doua sisteme laser diferite. Sistemul de control realizeaza in esenta corelarea in timp real a drumurilor optice corespunzatoare celor doua amplificatoare laser. Lucrarea prezinta principiul metodei, descrierea sistemului de control, precum si rezultate preliminare obtinute in laborator.
10:00 - 10:15
Title: Spectral brodening and pulse compression on thin film plastic materials
Author: Jonathan Wheeler
Abstract: The Thin Film Compression (TFC) technique (1) makes use of the excellent beam spatial uniformity and the high peak power of new high power laser systems. The unfocused, freely-propagating beam interacts with a thin, sub-millimeter film material to broaden the spectral bandwidth of the pulse by driving the nonlinear process of self-phase modulation (SPM). The spectrally broadened, chirped pulse is then compressed by reflection on a series of dispersion-controlled, “chirped” mirrors designed to compensate the spectral phase that results from the laser-material interaction. The experimental design relies principally on the introduction of a passive, transmissive thin film within the beamline followed by a number of specialized transport optics that act to sample the beam and compensate the pulse dispersion. The simple design proposed promises to allow for simple integration within existing beamlines in order to provide shorter pulse options, and higher peak intensities. Such novel few-cycle, high intensity pulses applied within ultra-relativistic plasma dynamics are shown through simulations to be of interest for electron and ion acceleration (2) as well as to further compress the pulse with a relativistic plasma mirror to produce coherent, attosecond timescale pulses of keV photons.(3) 1. G. Mourou, S. Mironov, E. Khazanov, and A. Sergeev. Single cycle thin film compressor opening the door to Zeptosecond-Exawatt physics. EPJ- Special Topics, 223(6), 1181 (2014). 2. M. L. Zhou, X. Q. Yan, G. Mourou, J. A. Wheeler, J. H. Bin, J. Schreiber, and T. Tajima Proton Acceleration by Single-Cycle Laser Pulses Offers a Novel Monoenergetic and Stable Operating Regime. Phys. Plasmas 23, 043112 (2016). 3. S.V. Bulanov, N.M. Naumova, & F. Pegoraro. Interaction of an ultrashort, relativistically strong laser pulse with an overdense plasma. Phys. Plasmas 1, 745 (1994).
10:15 - 10:30
Title: Spectral broadening of laser pulses by nonlinear effect in inhibited coupling Kagome fiber
Author: Constantin DIPLASU
Abstract: Diagnostics of time evolution of relativistic plasma waves produced by high power laser pulses require generation of ultra-short probe beams comprising only few oscillation cycles of carrier wave. These very short laser pulses can be obtained by further shortening the pulses delivered by Ti:sapphire laser systems, using a second compression after the pulses were previously spectrally broadened. Spectral broadening of laser pulses in hollow core inhibited coupling fibers filled with noble gases at high pressure is presented.
10:30 - 10:45
Title: Single-shot autocorrelator for ultrashort laser pulse duration measurements
Author: Razvan Ungureanu
Abstract: Since electronic devices and even streak cameras are too slow for temporal measurements of femtosecond laser pulses, intensity correlation techniques are employed for this purpose. Optical second order autocorrelation technique is widely used for the measurement of laser pulses with duration at femtoseconds scale, where an electronic apparatus (e.g., a photodiode) would be too slow. The operation principle involves splitting a laser beam into two beams of equal intensity and overlapping them in a nonlinear crystal to produce second harmonic (SH) radiation. Since the intensity of the SH is proportional to the product of the intensities I (t) of the two beams, its measurement as a function of relative time delay between them would provide the recording of an autocorrelation function. The pulse duration of the laser pulse can be deduced from the autocorrelation function by means of FWHM width estimation of a spatial intensity profile assuming in the same time temporal shape of the laser pulse (e.g Gaussian). While, autocorrelation function is typically measured in a multi-shot scanning operation by introducing different delays between the two laser pulses this approach allow measuring pulse duration in ranging up to picosecond level.
11:15 - 11:30
Title: Particle acceleration mechanisms in laser-plasma interactions at CETAL PW laser
Author: Constantin DIPLASU
Abstract: Particle acceleration based on laser-plasma interaction is one of the main research topics at CETAL PW laboratory. First, basic, acceleration experiments are foreseen for the next period in order to validate the performance of such facility. The main acceleration mechanisms involved in solid target and gas jet experiments are presented, emphasizing some of the applications related to accelerated proton beams and electron beams, as well.
11:30 - 11:45
Title: Detection of laser-plasma based accelerated particles
Author: Georgiana Giubega
Abstract: In recent years, laser-plasma accelerated particles has been a fervent field of research and progress has been steady, due to their great importance for applications in spatial industry, medical therapy and imaging. Therefore, one of the research topic of the CETAL-PW group is particle acceleration in laser-matter interaction and their particular detection methods. The characteristics of such acceleration processes, e.g. short particle beam duration, low particle fluxes, strong electromagnetic pulses, require particular detection methods with high enough sensitivity while avoiding complex electronics. The detection methods usually used for laser-plasma accelerated particles are presented along with the required simulations for a proper detection specific to the CETAL-PW laboratory.
11:45 - 12:00
Title: Electromagnetic waves generation in fs laser-matter interactions
Author: Aurelian Marcu
Abstract: The electromagnetic pulses (EMP) produced as a result of high power laser-target interaction, represent a hot topic not only due to the physical mechanism which is not very well understood, but also due to its effects induced in biological materials. The absorption measurements were performed on different biological materials using few generator sources and several home-made and commercially available (both calibrated) antennas). EMP emission spectra acquired during the interaction of CETAL high power laser with targets of different composition and thickness were also performed. Emission spectra of laser-matter interactions and absorption spectra of biological materials are further presented compared and discussed
12:00 - 12:15
Title: Radiation Hardness Assessment (RHA) Studies and Tests on satellite onboard optoelectronic components and systems
Author: Bogdan Mihalcea
Abstract: The severe radiation environment in the cosmic space is a major challenge for satellite equipment, and Radiation Hardness Assurance (RHA) is accordingly important for mission hardware. Spacecraft missions require evaluating potential radiation damages, appropriate design to prevent these damages, as well as radiation hardness testing of critical components – traditionally performed at large accelerator facilities. Recently it was realized that laser-plasma acceleration (LPA) of charged particles might represent a new and efficient tool to perform radiation hardness testing, under similar conditions to the natural environment.
12:15 - 12:30
Title: PIC simulations for laser ion acceleration at CETAL PW facility
Author: Olimpia Budriga
Abstract: We study the interaction of an ultra-high intensity laser pulse with plastic flat-top cone targets with curved walls and cone targets with straight walls. We find the appropriate type, dimensions of the cone target, and the ultra-high intensity laser pulse parameters for which the accelerated ions have the maximum energy and their number is the highest for a lower angular divergence and a better laser absorption. This numerical study will allow to prepare and optimize first laser ion acceleration experiments on CETAL PW facility using micro-cone targets.
12:30 - 12:45
Title: Random filamentation in the propagation of ultra-short laser pulses
Author: Florin Spineanu
Abstract: We start from the exact integrability of the elementary self-focusing propagation (gas Chaplygin with anomalous polytropic) and show that the analytical model for the intensity can be extended on physical basis to include the potential barrier separating two states of equilibria and the drive due to competing Kerr and MPI nonlinearities. We underline the variational structure and calculate the width of a branch of the cluster of high intensity (when it is saturated at a finite value). Our result is smaller but satisfactorily in the range of the experimental observations.
14:00 - 14:15
Title: Nanostructurated targets synthesis for proton beam acceleration through high laser power irradiation
Author: Ion Sandu
Abstract: Laser-driven particle acceleration has become a growing field of research, in particular for its numerous interesting applications. One of the most common proton acceleration mechanism is based on the irradiation of thin solid metal foils by the intense laser, generating the proton acceleration on its rear target surface. The eficiency of this acceleration scheme strongly depends on the laser-to-target absorption, where obviously cheap and easy to implement targets are best candidates. In this work, we present nanostructured targets that are able to increase the absorption of light compared to what can be achieved with a classical solid (non-nanostructured) target and are produced with a method that is much simpler and cheaper than conventional lithographic processes [1]. The alternative to lithographic processes is so called ” Natural Lithography”. On a Ti foile, we can deposit a SiO2 nanosphere colloidal drop which, in some specific conditions, can form a ordered nanosphere single-layer (Fig. 1a). A monomer or polymer solution ca be infiltrated to the nanospheres and, depending on its concentration, will form after its casting thin nests at each nanosphere bottom. After SiO2 nanosphere removing trough their dissolution in HF acid, we will obtain a polymeryc nanostructured thin film (Fig. 1b) of protons donor. The film thickness can be tuned by varieing soltion concentration and, the polymer nanostructured density by chousing nanospheres with a t propper size (Fig. 1c) References: [1] S. Vallieres,, Laser-driven proton acceleration with nanostructured targets, Proc. of SPIE Vol. 10240 1024009-1
14:15 - 14:30
Title: ISOTEST LABORATORY: capabilities, recent and not so recent results
Author: Alexandru Zorila
Abstract: We present the capabilities of the automated test stations for evaluation of laser induced damage threshold according to ISO standards, one station with pulses in the nanosecond regime and one in the femtosecond regime, and the mobile setup for laser beam characterization (measurement of the energy/power, M2 ratio and other propagation parameters). Also, we present some measurements on the nanosecond test station on antireflective coating and silver coated samples provided by SC IOR SA (PN-II-PT-PCCA-2013-4-0412 LIDOPTICS Project); CETAL beam transport mirror witness sample measured in the femtosecond test station.
14:30 - 14:45
Poster presentation
Title: Synthesis of materials using the High Voltage Anodic Plasma
Author: Cristina Surdu-Bob
Abstract: Vor fi prezentate capabilitatile sursei de plasma in ceea ce priveste sintetiza materialelor.
6 iulie 2017 - Ziua PhIL
9:00 - 9:30
Title: Prezentarea laboratorului PhIL
Author: Felix SIMA
Abstract: Research fields of PhIL include spectroscopic characterization, biophotonics, optical metrology and fiber optics and vibrometry. PhIL offers integrative photonic solutions to complex problems in material research, optics and life sciences. We perform multi-disciplinary research, from fundamental science to applied work to solve problems in material science, optical and metrological characterization and cell biology. PhIL is focusing on application and development of optical characterization techniques to the study of solid-state and biological phenomena at micro- and nanoscale. New technologies are applied and developed for material characterization, optical interrogation and study of phenomena at cellular level. Biophotonics research focuses on the development of innovative photonic devices and optical characterization methods and imaging to study cells at interaction with different materials and their functions at microscopic and nanoscopic scales. New designs and development of microfluidic systems and lab-on-a-chip devices are attempted as platforms for cellular testing.
9:30 - 9:45
Title: High repetition rate picosecond UV and VIS laser fabrication of 3D embedded structures in photosensitive glasses
Author: F. Jipa, S. Iosub, B. Calin, F. Sima
Abstract: Photosensitive glasses are alternative solutions to photoresists for the fabrication of 3D microstructures, in particular for biochip manufacturing. They are biocompatible and exhibit good transparency for optical interrogation, superior strength for easy handling and chemical resistance. NIR femtosecond lasers are the most used nowadays for transparent photosensitive glass processing of 3D complex shapes. In this work we propose a new approach for the fabrication of true 3D structures in photosensitive glasses by high repetition picosecond laser processing. Different shapes, such as micro-channels and reservoirs, generally used in the biochips design, are achieved in volume of the glass by picosecond laser irradiation followed by thermal treatment and wet chemical etching. The influence of the laser energy and scanning speed on the roughness of the fabricated structures is discussed together with a comparison between the 355 nm and 532 nm wavelength processing. Several advantages such us a reduced processing time for large areas and low fabrication cost are evidenced
9:45 - 10:00
Title: Fast picosecond laser fabrication of complex 3D embedded structures in photosensitive glass for dynamic gradient formation of biomolecules
Author: Stefana Iosub
Abstract: Lab-on-a-chip biological platforms were intensively developed during the last decade when emerging technologies offered possibilities to manufacture reliable devices with increased spatial resolution. These biochips allow testing chemical reactions in nanoliter volumes with enhanced sensitivity and lower consumption of reagents. There is a space to further consolidate the biochip assembling processing since the new technologies attempt direct fabrication in view of reducing costs and time by increasing efficiency and proposing specificity. Rapid prototyping by ultrafast lasers induces local modifications inside the transparent materials with high precision at micro- and nanoscale. Herein we report on the 3D fabrication of complex microfluidic structures consisting of open reservoirs connected through embedded channels in photosensitive glass by picosecond (ps) laser processing. The nonlinear absorption can confine the material modifications at the focal volume inside the transparent materials while high resolution CAD-CAM movable stages potentiate the 3D ps laser capability of creating the complex structures in three dimensions. Laser irradiation (λ=532 nm, τ<15ps) followed by thermal treatment and wet chemical etching of photosensitive glasses permitted us to fabricate true 3D micro-channels embedded in volume, with high precision. Channel surface characteristics and depth measurements were evaluated by profilometry, optical and scanning electron microscopy and interferometry, respectively. A microfluidic structure with 3D complex design was then proposed for dynamic gradient formation of biological relevant molecules.
10:00 - 10:15
Title: Automatic evaluation of quantum cascade lasers
Author: Petrisor Bleotu
Abstract: The applications of Quantum Cascade Laser diodes (QCL) in medicine, homeland security, remote sensing of gases and pollutants, plasma chemistry require an accurate evaluation of their characteristics in order to tune them to specific application needs. Thereby, we report two types of QCLs evaluation: one with manual wavelength tuning (Pranalytica Monolux: QCL 54 (4.91 - 5.33 µm) and QCL 72 (7.14 - 7.45 µm) and the second with driving current and temperature tuning using an automatic setup. For the first 2 QCL’s lasers data collection was achieved thought manually measurements of optical power, central wavelength, emitted spectrum, beam profile, divergence and M^2 factor, for 20 selected wavelengths. For the third QCL we develop an automatic setup controlled by a LabVIEW program, achieving a much faster and more accurate data acquisition than those already reported in literature [1, 2]. The advantages of using the LabVIEW programming environment for the automation control of the setup reduced the acquisition time and provide a 5-digit accuracy for the experimental data, by handling simultaneously several instruments: QCL’s driver/ temperature controller, a power meter, a wavelength meter, a spectrum analyser and a laser beam analyser. In this way, data are collected under different QCL operating conditions: temperature, driving current, and temporal stability, all of them in the frame of a single measurement. The proposed setup and the associated software offer a reliable, high speed and accurate testing of QCLs under different operating conditions required by specific applications. References: [1]. P. Patimisco, L. Mihai, M. Giglioa, A. Sampaoloa, P.P. Calabresea, J. M. Krieselc, D. Sporea, G.Scamarcioa, F. K. Titteld, and V. Spagnolo, “Hollow-core waveguide for single-mode laser beam propagation in the spectral range of 3.7-7.3 μm”, ResearchGate, DOI: 10.1117/12.2209533, 2016. [2]. P. Patimisco, A. Sampaolo, L. Mihai, M. Giglio, J.Kriesel, D. Sporea 3, G.Scamarcio, F. K. Tittel and V. Spagnolo ,” Low-Loss Coupling of Quantum Cascade Lasers into Hollow-CoreWaveguides with Single-Mode Output in the 3.7–7.6 um Spectral Range”, Sensors, 2016.
10:45 - 11:15
Title: UV-Mid - IR and THz spectroscopy for material science and environment testing
Author: Dan SPOREA, Laura MIHAI
Abstract: This paper presents our laboratory expertise in optical and THz characterizations using CETAL infrastructure: the OL750 spectroradiometer from Ghooch&Housego and the THz spectrometer TPS3000 from Tera View. We will present: - the results obtained within "Evaluation of Components for Space Applications" – ECSA project financed by Romanian Space Agency, providing informations on Mid –IR materials, detectors and Quantum Cascade Lasers to be used in harsh environments. These researches bring some novelties in the field: i) THz imaging and spectroscopy on the evaluation of optical materials and optical fibers; ii) study of QCLs degradation and Mid-IR detectors under different ionizing radiation exposure. - Study of tunable QCLs coupling to hollow core waveguides, reported in cooperation with University of Bari (COST Action MP1204). - Our expertise on spectrometers radiometrical characterization (radiance, irradiance and spectral characterizations), as a result of our international cooperation within COST Action ES 1309 – OPTIMISE network, with University of Edinburg and University of Zurich. - Optical and THz spectroscopy investigations on irradiated polymers and materials used for solar cell will be presented (COST Action MP1307 StableNextSol, colaborations with HOSLT Center from Netherlands, Institute of Physics from Czech Republic and Institute of Technologies from Portugal). - THz imaging investigations on ceramic materials stress induced by shocks and vibrations.
11:15 - 11:30
Title: Investigations of radiation effects on optical fiber sensors and silicon detectors
Author: Andrei Stancalie
Abstract: In the frame of national financed projects and international collaborations our work focused on characterization of radiation effects induced to a) optical fiber sensors of different types (fiber Bragg gratings, draw tower gratings, long period gratings or distributed sensors) b) novel solid-state silicon detectors with single photon counting capability (silicon photomultipliers). Extended studies have been carried out within collaborations through COST Action TD1001 with a) Department of Engineering, University of Naples “Parthenope” : Tests of gamma and neutron effects on long period gratings, custom produced by the group in Naples by electric arc discharge technique in commercial and radiation hardened single mode (SM) optical fibers b) Tests of gamma effects on LPGs produced by ”National Agency for nuclear waste management, ANDRA” (France) c) Testing Bragg gratings in radiation hardened optical fibers under electron beam irradiation in cooperation with the Institute of Photonic Technology, Jena, Germany; Within the cooperation with SiPM producers KETEK GmbH, Munich, Germany, in the frame of COST action TD1401, detectors of different types and produced by different technologies were subjected to gamma ray, electron beam, alpha particles and protons irradiation. Tests were carried both at Munich and CETAL Department to establish induced effects on main parameters of the SiPMs such as IV-CV characteristics, dark current or photon detection efficiency.
11:30 - 11:45
Poster presentation
Title: Chemical composition identification of dental implants by Laser Induced Breakdown Spectroscopy
Author: Andrei Stancalie
Abstract: We present in this work, the chemical composition identification of several commercial dental implants by Laser Induced Breakdown Spectroscopy (LIBS). Due to its advantages, such as real time monitoring of ablated species, fast and spatially precise, LIBS is a promising and suitable tool which permits analysis of hard materials, in small amounts with no sample preparation necessary. Our research focuses on chemical composition identification and detection of contaminants and defects that may occur due to superficial processing of commercially available dental implants. The system we used in our study integrates a Nd:YAG laser source at 1064 nm with tunable energy up to 197 mJ. Recorded spectra from the resulted plasma are collected by six spectrometers displayed around the target within the range of 200 to 900 nm. After optimization of processing parameters, similar conditions were kept for all samples. The energy was set to 50 mJ per pulse for 40 accumulation laser pulses with a 10 Hz repetition rate and 1.27 µs delay. For the chemical identification of components, the main emission lines and spectroscopy data were extracted from NIST Database, to be compared with experimental results. For each sample, multiple irradiations were conducted, in different distinct regions. Irradiated samples were manufactured of titanium or titanium alloy like the commercial Ti-6Al-4V alloy. Preliminary results confirm the presence of Ca (Ca I 422.67 nm). Complementary studies by energy-dispersive X-ray spectroscopy accompanied by morphological investigations by scanning electron microscopy are presented to support LIBS investigations.
11:45 - 12:00
Title: Single pixel camera and THz wave imaging
Author: Tiberius Vasile
Abstract: The aim of this presentation is to shed some light on the concept and applications of single-pixel camera and also its potential for THz wave imaging. From a technological point of view imaging THz waves has been always difficult. Silicon based detector arrays are ineffective for this type of radiation and state of the art THz imaging sensors are underdeveloped or incapable to cover its entire bandwidth. In this context, a single pixel camera might offer better performance in terms of image acquisition, resolution, spectral coverage as well as reduced complexity (one detector), active pixel sizing and higher signal to noise ratio (SNR).