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Projeto de investigação
500 W-class visible solar pumped alexandrite lasers for aluminium welding applications
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Seven-Rod Pumping Concept for Highly Stable Solar Laser Emission
Publication . Costa, Hugo; Liang, Dawei; Almeida, Joana; Catela, Miguel; Garcia, Dário; Tibúrcio, Bruno D.; Vistas, Cláudia R.; DF – Departamento de Física; CeFITec – Centro de Física e Investigação Tecnológica; MDPI - Multidisciplinary Digital Publishing Institute
A seven-rod solar laser head was conceptualized and numerically studied to improve the tracking error compensation capacity and power stability in end-side-pumping schemes. It was composed of a first-stage heliostat–parabolic mirror system, a second-stage fused silica aspheric lens and a third-stage conical pumping cavity, within which seven Nd:YAG rods were mounted. Highly stable solar laser emission, with a power loss inferior to 5% for tracking errors up to ±0.4°, could potentially be enabled with seven 4 mm diameter, 13 mm length rods. The tracking error width at 10% laser power loss was about 1.0°, which is 1.65 times higher than the experimental record, attained by a dual-rod side-pumping prototype. Furthermore, a total multimode laser power of about 41.2 W could also be achieved, corresponding to 23.3 W/m2 collection and 2.5% solar-to-laser power conversion efficiencies, which are 1.65 and 1.36 times higher than those obtained with the dual-rod side-pumping prototype. They are also 1.27 and 1.12 times higher than the multirod experimental records in multimode regime for the same rod material.
Quasi-Gaussian Multibeam Solar Laser Station for a Megawatt Solar Furnace
Publication . Costa, Hugo; Almeida, Joana; Liang, Dawei; Tibúrcio, Bruno D.; Garcia, Dário; Catela, Miguel; Vistas, Cláudia Alexandra da Rocha; DF – Departamento de Física; CeFITec – Centro de Física e Investigação Tecnológica
An alternative multirod solar side-pumping concept for the production of multiple quasi-Gaussian beams is proposed. This scheme was based on the One-Megawatt solar furnace in Odeillo, France, which collected and concentrated the solar light into a multilayered pyramidal pumping cavity placed at the focal zone. Each layer was comprised of a square array of four laser heads, each composed of a biconic surface that reflected the solar rays towards a Nd:YAG rod fixed inside a fused silica flow tube. A pyramidal reflector was placed inside the pumping cavity to close it and maximize the harness of solar energy. Compared to the previous multibeam solar laser station design for the same solar furnace, considerable alleviation of thermal lensing effects was achieved with the present approach, allowing the improvement of the laser beam quality factors and, consequently, the possibility of a 32-laser-beam generation, each with a quasi-Gaussian profile. For this case, 9.44 kW total laser power was calculated. Additionally, 20.01 kW total multimode laser power was numerically determined, which corresponds to a 10.93 W/m2 collection efficiency and a 2.0% solar-to-laser power conversion efficiency.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
FARH
Número da atribuição
PD/BD/128267/2016