RICARDO ELGUL SAMAD

RICARDO ELGUL SAMAD

(Fonte: Lattes)

Resumo

Has graduation at Bacharelado Em Física by Instituto de Física da Usp (1993) , specialization at V Escola Jorge André Swieca de Óptica Quântica by Centro Brasileiro de Pesquisas Físicas (1996) , specialization at 1a Escola de Óptica Aplicada by Instituto de Física da Usp (1998) , specialization at Training Course On Instrumentation For Ultrashort by International Centre For Science And High Technology (2002) , specialization at An Introduction to Femtosecond Laser Techniques by The International Society For Optical Engineering (2005) , specialization at IV Escola Jorge André Swieca de Óptica Quântica by Universidade Estadual de Campinas (1994) , specialization at Workshop On Thin Films by International Centre For Theoretical Physics (1999) , specialization at Winter College On Optics by International Centre For Theoretical Physics (1998) , specialization at Winter College On Ultrafast Non Linear Optics by International Centre For Theoretical Physics (2002) , master's at Física do Estado Sólido by Instituto de Física da Usp (1997) and Ph.D. at Física do Estado Sólido by Instituto de Física da Usp (2006) . Currently is of Instituto de Pesquisas Energéticas e Nucleares, Revisor de periódico of Applied Optics, Revisor de periódico of Optics Letters, of Universidade de São Paulo, Revisor de periódico of Journal of Applied Physics, of Comissão Nacional de Energia Nuclear, Revisor de periódico of OPTICS EXPRESS, Revisor de periódico of OPTICS AND LASERS IN ENGINEERING, Revisor de periódico of JOURNAL OF APPLIED PHYSICS, Revisor de projeto de fomento of Conselho Nacional de Desenvolvimento Científico e Tecnológico, Revisor de projeto de fomento of Fundação de Amparo à Pesquisa do Estado de São Paulo, Revisor de projeto de fomento of Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Revisor de periódico of Papers in Physics, Revisor de periódico of Optics and Laser Technology, Membro de corpo editorial of SBFoton Newsletter, of University of Nebraska/Lincoln e of Centro Tecnológico da Marinha Em Sao Paulo. Has experience in the area of Physics , with emphasis on Física da Matéria Condensada. Focused, mainly, in the subjects: femtossegundos, Terawatt, Cr:LiSAF, Amplificacao de Pulsos Laser, Lasers. (Text obtained from the Currículo Lattes on November 25th 2021)

Ricardo Elgul Samad bacharelou-se em Física em 1993, obteve o seu mestrado em Física do Estado Sólido em 1997, e concluiu o doutorado também em Física do Estado Sólido em 2006, todos pelo Instituto de Física da USP. Atualmente é Pesquisador do Centro de Lasers e Aplicações Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP). Publicou 69 artigos em periódicos especializados que possuem mais de 550 citações, 3 capítulos de livros e mais de 90 trabalhos em anais de eventos, além de ter submetido 2 pedidos de patente. Desde a sua Iniciação Científica trabalha no desenvolvimento e em aplicações de lasers de estado sólido, e no seu doutorado iniciou atividades de pesquisa com lasers de pulsos ultracurtos. Atualmente trabalha com aplicações de pulsos ultracurtos e a interação destes com a matéria, como na ablação e usinagem de sólidos por laser, geração de plasma induzida por pulsos ultracurtos e modificação de materiais resultante de estados extremos de temperatura e pressão gerados pelos pulsos ultracurtos, e técnicas de geração de harmônicos para viabilizar novas fontes de luz na região do UV profundo e raios X moles. Recentemente tem trabalhado com aceleração de partículas por pulsos laser ultracurtos. (Texto extraído do Currículo Lattes em 25 nov. 2021)

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FTIR imaging on glass substrates evaluation of histological skin burn injuries specimens treated by femtosecond laser pulses
2022 - ZEZELL, DENISE; CASTRO, PEDRO; DEL-VALLE, MATHEUS; CAMILLO-SILVA, CARLOS; SAMAD, RICARDO; DE ROSSI, WAGNER; SANTOS, MOISES
Burn injuries continue to be one of the leading causes of unintentional death and injury in low- and middle-income countries [1]. Burns are considered an important public health problem, because in addition to physical problems that can lead the patient to death, they cause psychological and social damage. An estimated 180,000 deaths every year are caused by burns [2]. The use of infrared (IR) spectroscopy for studying biological specimens is nowadays a wide and active area of research. The IR microspectroscopy has proved to be an ideal tool for investigating the biochemical composition of biological samples at the microscopic scale, as well as its fast, sensitive, and label-free nature [3]. IR image spectral histopathology has shown great promise as an important diagnostic tool, with the potential to complement current pathological methods, reducing subjectivity in biopsy samples analysis. However, the use of IR transmissive substrates which are both fragile and prohibitively very expensive, hinder the clinical translation. The goal of this study is to evaluate the potential of discriminating healing process, in burned skin specimens treated with ultrashort pulses laser 3 days after the burn. This study is considering a previous paper [4], in which it analyzed only micro-ATR-FTIR spectra of a frozen sample point. The specimens were obtained from third degree burn wound. The wounds treatment were performed three days after the burn, and the animals were sacrificed 3 and 14 days post-treatment. Using coverslipped H&E stained tissue on glass from previous histopathological analysis and applying the analytical techniques PCA and K-means on N−H, O−H, and C−H stretching regions occurring at 2500−3800 cm−1 (high wavenumber region), were possible to discriminate burned epidermal and dermal regions from irradiated in same regions on sample. In the figures is shown the average spectrum at (a) day 3 and (b) day 14. , in both there were increase of burned+laser treated bands. The great potential of this study was to analyse coverslipped H&E stained tissue on glass, without compromising the histopathologist practices and contribute for clinical translation.
Determination of parameters for micromachining of microfluidic mixers with complex geometry in glass using ultra-short laser pulse
2022 - GOMES, ANTONIO A.; VIANNA JUNIOR, ARDSON dos S.; MOREIRA, GREGORI de A.; LANDULFO, EDUARDO; SAMAD, RICARDO E.; BERNARDES, EMERSON S.; ROSSI, WAGNER de
Femtosecond laser micromachining was adopted to make a glass mixer with complex geometry. This special design promotes more efficient mixing in microreactor with gas-liquid flux at low flow rates, compared to conventional serpentine mixers.
Ultrashort laser pulse microtexturing on cutting tools
2022 - ROSSI, WAGNER de; GOMES, ANTONIO A.; SAMAD, RICARDO E.; MACHADO, ALISSON R.; CHELIGA, PEDRO A.B.
Femtosecond laser pulses were used for texturing cutting tools in order to obtain better results in the traditional metal turning process. Some significant examples are presented in this work.
High intensity ultrashort laser pulses and their applications at IPEN
2021 - SAMAD, RICARDO E.; MALDONADO, EDISON P.; ROSSI, WAGNER de; VIEIRA JUNIOR, NILSON D.
Ultrashort laser pulses interact with matter in unique, nonselective ways, due to electronic direct excitation in an ultrafast time scale. Additionally, these pulses can cover peak powers from kW to PW, allowing its use to induce from nonlinear optics up to relativistic phenomena. Here we present a quick overview of the important processes induced in matter by high-intensity ultrashort pulses, and describe results obtained in our laboratory, including our most recent goal of accelerating electrons with ultrashort pulses for practical applications.
Study of ablation on surfaces of zircaloy Z-4 irradiated with femtosecond laser
2019 - GUANABARA JUNIOR, PAULO; NOGUEIRA, ALESSANDRO F.; SAMAD, RICARDO E.; ROSSI, WAGNER de
The use of ultrashort femtosecond laser pulses is an alternative for micro machining on metal surfaces, with several industrial applications, in such areas as aeronautics, aerospace, naval, nuclear, among others, where there is growing concern about service reliability. Thus, markings for traceability purposes should ensure the integrity of the metal as well as allow reading of the marked characters, whether automated or not. In this work, micro machining of zircaloy Z 4 surfaces using femtosecond laser was performed aiming at the knowledge of the ablation threshold and Scanning Electron Microscopy (SEM) analysis in different images. Obtained from micro machined traces, energy fluence parameters and laser pulse overlap. The amount of ablated material in this femtosecond laser micro machining is negligible, which contributes to ensuring that there is no mi crostructural damage. Such a process resulted in different images, which characterize that there are different optical properties because of the parameters change.
Avaliação do desempenho de ferramenta de metal duro texturizada por laser de pulsos ultracurtos
2019 - ALMEIDA, GUSTAVO S. de; COELHO, REGINALDO T.; CARNEIRO, MARCELO B.; BARBOSA, PATRICIA A.; ROSSI, WAGNER de; SAMAD, RICARDO E.; VIEIRA JUNIOR, NILSON D.; MACHADO, ALISSON R.
A texturização por laser de pulsos ultracurtos provoca uma ablação com mínimo dano térmico, preservando as características adjacentes do material ablacionado. Deste modo, torna-se possível gerar microtexturas na superfície de saída da ferramenta de usinagem, buscando melhoria de desempenho. Este trabalho realiza uma comparação entre duas ferramentas de corte de metal-duro, TPUN 160304, sendo uma texturizada e a outra de referência (nãotexturizada), durante o torneamento de um aço inoxidável austenítico (V304UF). Para isto, os parâmetros de corte foram mantidos constantes. Avaliou-se a força de usinagem, o desgaste de flanco da ferramenta, além da rugosidade produzida sobre a peça. Os resultados mostraram um melhor comportamento para ferramenta texturizada.
Modifying the second order dispersion of femtosecond laser pulses to crack silver nanoparticles and control their dimensions
2019 - CORDEIRO, THIAGO da S.; AMARAL, MARCELLO M.; MATOS, RICARDO A. de; SILVA, FLAVIA R.O.; VIEIRA JUNIOR, NILSON D.; COURROL LILIA C.; ROSSI, WAGNER de; SAMAD, RICARDO E.
The potential application of metallic nanoparticles had been attracting attention and interest from different areas of academia and industry. The nanoparticles properties and applications depend heavily on their dimension and shape, thus special interest is aimed to controlling the nanoparticles sizes. Ultrashort laser pulses are known to change metallic nanoparticles characteristics, but the interaction mechanism is still not completely understood. In this work we reduced the dimension of silver nanoparticles with ultrashort pulses and demonstrated that there is a dependence of the particles size on the second order dispersion introduced in the pulses, which became smaller as the dispersion becomes more negative. Based on the results, we propose that the Coulomb explosion that reduces the nanoparticles size is predominantly initiated by multiphotonic ionization for the intensities used (1014 W/cm2).
Focus tracking system for femtosecond laser machining using low coherence interferometry
2019 - RAELE, MARCUS P.; DE PRETTO, LUCAS R.; ROSSI, WAGNER de; VIEIRA JUNIOR, NILSON D.; SAMAD, RICARDO E.
We designed a real time, single-laser focus tracking system using low coherence properties of the machining femtosecond laser itself in order to monitor and correct the sample position relative to the focal plane. Using a Michelson Interferometer, the system collects data arising from part of the beam backscattered at the ablation spot. The data is analyzed by a custom software for position correction (employing an XYZ automated translation stage). With the focus tracking enabled we were able to etch channels with a stable cross-section profile on a bovine tooth with relief amplitude tens of times greater than the Rayleigh length of the system, keeping the sample inside the confocal parameter during most of the processing time. Moreover, the system is also capable of monitoring crater depth evolution during the ablation process, allowing for material removal assessment.
High intensity femtosecond lasers at IPEN
2018 - SAMAD, R.E.; MALDONADO, E.P.; COURROL, L.C.; ROSSI, W. de; BALDOCHI, S.L.; ZEZELL, D.M.; VIEIRA JUNIOR, N.D.
High intensity femtosecond (fs) lasers have become an affordable and versatile tool to modify all kinds of materials and to characterize the induced modifications. These capabilities derive from the ultrafast interaction between the electromagnetic field and matter, which distinguishes this kind of laser from all others. In the time frame of the fs pulses, the predominant interaction with the matter occurs through electron excitation, and several processes take place with increasing intensity: nonlinear excitation, ionization and recombination, which occur in a non-selective way due to the short time of interaction. The after-pulse evolution is due mainly to electrostatic interactions, involving the relaxation of the electrons energy to and between atoms. Coulomb and phase explosions, for example, are predominant for intensities in the range of TW/cm2 to PW/cm2, and they ablate all material (metals, polymers, dielectrics, etc) with a very high precision due to the small heat effect zone of these interactions. At the High Intensity Ultrashort Pulses Lasers Laboratory at IPEN we daily generate femtosecond pulses with intensities of 100 TW/cm2 and above. In this work we describe results obtained by our group using ultrashort pulses from Ti:Sapphire lasers covering the creation of color centers in crystals, glasses and polymers, the inscription of waveguides and the creation of surface structures that can range from the colorization of metals to the manufacture of microfluidic circuits, as well as the removal of burned tissue from living organisms. The pulses can also be used to study how defects pileup during the etching of a solid by superimposing pulses, and how the ablation process is affected by the incubation. At higher intensities the pulses can modify materials, and we present the controlled synthesis of nanoparticles, and the modification of graphite into diamond by the shockwaves generated during the ablation as a product of an evolving underdense plasma that generates local high temperatures and pressures. Also, the materials characterization is possible by spectroscopic measurements of the plasma elements atomic lines. Furthermore, we present results on the production of radiation on the deep ultraviolet by generation of harmonics of the laser interaction with gases, and also our recent efforts towards the acceleration of electrons by ultrashort laser pulses. Both the harmonics and electrons ultrafast beams could be used to modify and characterize materials by pump-probe, spectroscopic and diffraction measurements.
Redução do atrito por meio da texturização a laser com pulsos ultracurtos do aço DIN 16MnCr5
2018 - VIEIRA, ALEXANDRE; SAMA, RICARDO E.; JUNIOR, NILSON D.V.; ROSSI, WAGNER de
A indústria automobilística tem como um de seus principais desafios, e consequentemente, foco de pesquisa, a redução do coeficiente de atrito entre alguns componentes e sistemas presentes nos automóveis. Um dos grandes benefícios dos avanços nesta área é o aumento da vida útil dos componentes e a melhor eficiência do motor. Desta maneira, uma das formas propostas pela tribologia para a redução de atrito é a texturização de superfícies por laser. Neste trabalho, foi abordada a interação de pulsos laser com largura temporal na ordem de femtossegundos com o aço DIN 16MnCr5, utilizado na indústria automotiva. Objetivou-se buscar os melhores parâmetros de processo para obter micro cavidades com pouca ou nenhuma zona afetada pelo calor e sem a presença de rebarbas e material ressolidificado, normalmente presentes na texturização com laser de pulsos longos (nanossegundos). Para a realização do estudo foi utilizada a técnica de escaneamento diagonal, D-Scan, para determinação dos limiares de ablação em função da sobreposição de pulsos. Também foram realizados estudos de formação das cavidades com a variação da posição do ponto focal e do perfil espacial do feixe laser. São apresentados resultados de análises obtidas por microscopia óptica e de varredura e interferometria de luz branca, além de resultados dos ensaios tribológicos que mostraram redução de mais de 10% da força e coeficiente de atrito.