NIKLAUS URSUS WETTER

NIKLAUS URSUS WETTER

(Fonte: Lattes)

Resumo

Niklaus Ursus Wetter holds a BA in Physics from the Eidgenössische Technische Hochschule Zürich - ETH (1988 - Switzerland) and a Ph.D. in Nuclear Technology from the Institute for Energy and Nuclear Research (1993). He is currently a senior researcher at the National Nuclear Energy Commission at IPEN / SP and a postgraduate professor at the University of São Paulo ? USP, where he regularly teaches a subject. From 2009 to 2013 he was deputy manager of the Center for Lasers and Applications at IPEN / SP. From 2013 to 2018 he held the position of manager of the Center for Lasers and Applications at IPEN / SP. From 2014 to 2020 he held the position of CEO of FAFITPE, IPEN's Foundation for Support and Promotion of Technological Innovation in Research and Education. Since 2019 he has held the position of Deputy Director of Research and Internationalization Manager at IPEN. As manager of Internationalization, he has so far implemented 14 bilateral agreements with universities and institutes around the world, including the Battelle Energy Alliance, which encompasses eight of the largest federal research institutions in the US. In 2018 he was responsible for organizing the André Swieca Summer School and the São Paulo School of Advanced Science FAPESP "Laserfrontiers.com" with 141 students, 40 of whom came from outside Latin America. He specializes in laser development and operates in the main segments: Diode lasers, waveguides, solid state lasers, laser applications in life sciences, lasers in nuclear applications, optical spectroscopy and materials for laser media in general. Since 2008 he has been developing light sources in disordered materials, or "Random Lasers", for the purpose of applications in optical devices. In 2017, he acquired, through a FAPESP project, a Raman-TERS (AFM) multiuser equipment with STM and SNOM, focused on measurements and development of nanomaterials. He has 4 patent letters and 7 applications in total, 190 international articles with over 2000 citations and an h factor of 26 (Scopus). (Text obtained from the Currículo Lattes on October 14th 2021)

Niklaus Ursus Wetter é bacharel em Física pela Eidgenössische Technische Hochschule Zürich - ETH (1988 - Suíça) e Doutor em Tecnologia Nuclear pelo Instituto de Pesquisas Energéticas e Nucleares (1993). Atualmente é pesquisador titular da Comissão Nacional de Energia Nuclear no IPEN/SP-USP e docente de pós-graduação da Universidade de São Paulo ? USP, onde ministra regularmente uma disciplina. De 2009 a 2013 foi gerente adjunto do Centro de Lasers e Aplicações do IPEN/SP. De 2013 até 2018 ocupou o cargo de gerente do Centro de Lasers e Aplicações do IPEN/SP. De 2014 até 2020 ocupou o cargo de diretor-presidente da FAFITPE, Fundação de Apoio e Fomento a Inovação Tecnológica a Pesquisa e ao Ensino do IPEN. Desde 2019 ocupa o cargo de Vice-diretor de Pesquisa e gerente de Internacionalização do IPEN. Na função de gerente da Internacionalização, ele implementou até agora 14 acordos bilaterais com universidades e institutos de toda parte do mundo, entre estes a Battelle Energy Alliance que engloba oito das maiores instituições federais de pesquisa dos EUA. Em 2018 foi o responsável pela organização da Escola de Verão André Swieca e a Escola São Paulo de Ciencia Avançada FAPESP "Laserfrontiers.com" com 141 alunos dos quais 40 de fora da america latina. Foi editor associado das revistas Optics Express e Optical Materials Express e atualmente atua como editor associado da revista Frontiers, especialidade Optical Nanostructures. É especialista em desenvolvimento de lasers e atua nos principais segmentos: Lasers de diodo, Guias de onda, Lasers de estado sólido, Aplicações de lasers nas ciências da vida, Lasers em aplicações nucleares, Espectroscopia ótica e materiais para meios Laser em geral. Desde 2008 desenvolve fontes de luz em materiais desordenados, ou "Lasers Randômicos", para fins de aplicações em dispositivos ópticos. Possui 4 cartas de patente e 7 pedidos no total, 190 artigos internacionais com mais de 2000 citações e fator h de 26 (Scopus). (Texto extraído do Currículo Lattes em 14 out. 2021)

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Pump controlled Nd:YVO4 random laser
2024 - DIPOLD, JESSICA; KASSAB, LUCIANA R.P.; WETTER, NIKLAUS U.
Yttrium vanadate doped with neodymium crystal powder random laser have demonstrated promising results in 1064 nm emission when pumped at a wavelength of 806 nm. In this study, we show that by using a 585 nm pump wavelength, it is possible to achieve random lasing at both 1064 nm and 1340 nm, with the emission tunable through variations in pump intensity.
24 mJ single pulse energy from a Nd:YLF/Cr:YAG laser in a DBMC configuration
2024 - PRADO, FELIPE M.; FRANCO, TOMAS J.; WETTER, NIKLAUS U.
This work presents a high-power Nd:YLF/Cr:YAG laser in a Double Beam Mode Controlling configuration, achieving a single pulse energy of 24 mJ, with a pulse duration of 15 ns, emitting at 1053 nm. The configuration demonstrated significant improvements in beam quality, with measured M² values of 2.13 vertically and 2.42 horizontally when compared to single-pass configurations. These results highlight the effectiveness of the DBMC approach in enhancing beam quality while maintaining high energy output.
Sensitivity estimation for the future laser ionization diagnosis in inferring neutral particle density in the TCABR tokamak
2024 - ALBUQUERQUE, FERNANDO A.F.; WETTER, NIKLAUS U.; SEVERO, JOSE H.
This study undertakes an estimation of photoionization occurrences and the ensuing reduction in hydrogen spectral line intensities via Laser-Induced Ionization. The objective is to quantify the sensitivity of the neutral particle density diagnostic
Optical neural network for all-optical logic gates solution
2024 - WETTER, NIKLAUS U.; PRADO, FELIPE M.
With the escalating demand for speed and computational power to meet the ever-growing requirements of AI algorithms, coupled with the limitations of von Neumann computing, there is an increasing necessity for alternatives to silicon-based computers. Photonic computers emerge as a promising solution to this challenge, leveraging the low latency and parallelism of light to deliver unrivaled capabilities for neuromorphic computing. Notably, they offer significant reductions in energy consumption and substantial speed enhancements, allowing for matrix multiplications at the speed of light. These operations are particularly crucial as they constitute approximately 80% of computer usage in convolutional neural networks. In this work, we present an optical system capable of performing logic operations, such as AND, OR, NOT, and XOR, in an all-optical manner. This is made possible by utilizing a spatial light modulator (SLM), which receives and adjusts the input light according to the desired logic operation and input binary values. These values are encoded using a metal mask that segments a collimated light beam from a He-Ne laser. To incorporate not only the binary value of each bit but also the desired logic operation simultaneously, specific regions within a CCD sensor that receive the input beam after passing through the mask are defined. In a simplified approach, we designate the two lower quadrants of the CCD image to represent individual bits (lower left = bit 1; lower right = bit 2) and by detecting light intensity above a defined threshold, a logic value of '1' is assigned; otherwise, '0' is interpreted. Similarly, the same intuitive method can be applied to the upper quadrants to determine the logic operation (upper left = AND; upper right = OR). Further divisions of the CCD image can be implemented to accommodate additional operations or to create a bias beam, which is crucial for solving more complex problems. The analogy between this optical neural network and traditional networks can be drawn as follows: incident light on each SLM pixel forms the input vector, multiplied by a weight matrix via programmable phase delays. The resulting light, reflected by the SLM, is focused by a lens and captured by a CCD camera, effectively summing up the results to produce an output or new layer. The presented approach is particularly interesting for establishing a basis for future improvements and characterizations of optical non-linear activation functions.
Compact diode-pumped Nd:YLF laser with triple-wavelength emission
2024 - PRADO, FELIPE M.; FRANCO, TOMAS J.; WETTER, NIKLAUS U.
Here we present a compact and cost-effective Nd:YLF laser, capable of operating with either single- or multi-wavelength emission at 1047 nm, 1321 nm, or 1370 nm. The Nd:YLF crystal is side-pumped by a 797 nm emitting diode stack in a single-bounce resonator, featuring a concave highly reflective mirror with a radius of curvature of 8 m and a plane output coupler. The transmission of the laser mirrors is carefully selected to favor emissions with lower cross-sections, while still providing enough reflection for wavelengths with higher absorption. Through this technique alone, it was possible to select each wavelength or a combination thereof simply by aligning one laser mirror. This approach not only excels in terms of versatility, enabling multiple applications within the same laser setup, but also introduces innovative wavelength emission at 1370 nm. To the best of our knowledge, this represents the first reported instance of a transversally-pumped Nd:YLF emitting at this wavelength. This new wavelength holds great promise, primarily due to its proximity to the eye-safe region of the spectrum that can be achieved by additional Raman conversion. This characteristic opens a diverse range of potential applications, including Light Detection and Ranging (LIDAR), and range finding.
Morphodynamics drive the transport and accumulation of anthropogenic microparticles in tropical coastal depositional systems in southeastern Brazil
2024 - FURLAN, ISABELA; FORNARI, MILENE; SAWAKUCHI, ANDRE O.; GIANNINI, PAULO C.F.; DIPOLD, JESSICA; FREITAS, ANDERSON Z. de; WETTER, NIKLAUS U.; SEMENSATTO, DECIO
A significant limitation in current coastal pollution research is that microplastics (<5 mm) comprise only a fraction of all anthropogenic microparticles (AMP, <5 mm) scale residues. Comprehensive AMP assessments, including those comprising semisynthetic, and modified natural compositions, are lacking. For instance, the accumulation of AMP in different coastal morphological features within a depositional system remains poorly known, fueling long-lasting debates about the distribution process of microparticles. Using a multi-proxy approach, we address mutual interactions between distinct surface morphologies (tidal flats, beaches, and foredunes) and transport and deposition dynamics of AMP. This issue was addressed by analyzing sediment and water samples collected at a marine protected area in the south coastal of São Paulo (Brazil). Here, we showed that AMP abundance in the tidal mudflat (18,500–20,500 particles/kg) was four times higher than in beach sands (4700–5900 particles/kg), while the lowest abundance was observed in foredune sands (4350 particles/kg). This can be attributed to the low-energy hydrodynamics of tidal flats associated with the cohesive behavior of muddy sediments, which consequently favor trapping and act as the main sink for AMP. Further, coastal processes (waves and currents) drive AMP onshore through sediment transport from the surfzone to the beach, from where the AMP becomes available for onshore eolian transport. Higher AMP abundance (85 particles/l) was observed in the marine water samples compared to the estuarine water samples (35 particles/l). Fibers <1 mm appeared as the predominant AMP in the sediment (99–100 %) and water (80–95 %) samples, primarily consisting of modified cellulose (73 %), dye signature only (16 %), and microplastics (11 %). Consequently, we argue that to fully comprehend the spatial distribution of AMP in coastal sediments and waters, it is crucial to analyze these microparticles from an integrated perspective, primarily considering the hydro-wind dynamics of different coastal morpho-sedimentary compartments combined with sediment grain size.
Combination of micro-Raman and infrared spectroscopy to identify intriguing case of aged microplastics of estuarine sediments
2024 - SANTOS, JACINETE L. dos; BERECZKI, ALLAN; PASCOAL, DIEGO R. da C.; GIMILIANI, GIOVANA T.; COTRIM, MARYCEL E.B.; FREITAS, ANDERSON Z. de; WETTER, NIKLAUS U.; PARRA, DUCLERC F.
The Atlantic Forest is one of the richest regions in biodiversity in the world. Originally the biome covered around 15% of the Brazilian territory. Currently, there are approximately 12.4% of forest remnants preserved in the country. Regarding mangrove areas in the state of São Paulo, there are around 223 km2 according to the Brazilian Mangrove Atlas, with around 120.5 km2 located in Baixada Santista. Analysis of sediments found in the estuarine mangroves of Santos shows a high concentration of microplastics (MPs), generated by industrial processes and human activity, that constitutes today one of the main environmental problems. The MPs presented in the sediment samples are quantified using a methodology that involves drying, sieving, quantification, and identification of these MPs through FTIR and micro-Raman spectroscopy. The two techniques complement each other to identify MP filaments and fragments through common polymer spectra. Furthermore, the micro-Raman technique also identified additives flexo blue (blue ink) and neolan green 8G (dye) in MPs. All identified polymers (< 5 mm) have wide applications and demands in various sectors, including packaging, construction, automotive, electronics, and textiles.
Sub-nanosecond MW microchip oscillator for laser tattoo removal MOPA system
2024 - CATARINA, MARCUS V.; BERECZKI, ALLAN; WETTER, NIKLAUS U.
We investigate a Q-switched Nd:YAG laser aimed to work as an oscillator in a MOPA system for laser tattoo removal. Pulses of 4.8 MW peak power with 680 ps pulses were obtained.
Random laser emission at 1348 nm from Nd:YVO4 crystal powder
2024 - DIPOLD, JESSICA; WETTER, NIKLAUS U.
Nd:YVO4 powder random lasers have shown high efficiency in 1064 nm emission with 806 nm excitation. Here, by using 585 nm excitation, we show laser emission for 1348 nm for the first time.
Passive waveguide fabrication through femtosecond laser irradiation in Ag-doped GeO2–PbO glasses for photonic applications
2024 - FERNANDES, THIAGO V.; BORDON, CAMILA D.S.; WETTER, NIKLAUS U.; ROSSI, WAGNER de; KASSAB, LUCIANA R.P.
We present the fabrication of dual waveguides in Ge2O-PbO glasses doped with silver nanoparticles using direct femtosecond laser inscription. The study involves results of beam quality, propagation loss, and polarization of the dual waveguides.