Granados-Mateo, E. (Eduardo)
- Publications
- item.page.relationships.isContributorAdvisorOfPublication
- item.page.relationships.isContributorOfPublication
3 results
Search Results
Now showing 1 - 3 of 3
- LIPSS manufacturing with regularity control through laser wavefront curvature(Elsevier, 2021) Olaizola, S.M. (Santiago Miguel); San-Blas, A. (Alejandro); Martínez-Calderón, M. (Miguel); Gómez-Aranzadi, M. (Mikel); Rodríguez, A. (Ainara); Granados-Mateo, E. (Eduardo)Laser-Induced Periodic Surface Structures (LIPSS) manufacturing is a convenient laser direct-writing technique for the fabrication of nanostructures with adaptable characteristics on the surface of virtually any material. In this paper, we study the influence of 1D laser wavefront curvature on nanoripples spatial regularity, by irradiating stainless steel with a line-focused ultrafast laser beam emitting 120 fs pulses at a wavelength of 800 nm and with 1 kHz repetition rate. We find high correlation between the spatial regularity of the fabricated nanostructures and the wavefront characteristics of the laser beam, with higher regularity being found with quasi-plane-wave illumination. Our results provide insight regarding the control of LIPSS regularity, which is essential for industrial applications involving the LIPSS generation technique.
- Tailoring diamond's optical properties via direct femtosecond laser nanostructuring(Nature Research, 2018) Rodríguez, A. (A.); Azkona, J.J. (J. J.); Olaizola, S.M. (Santiago Miguel); Casquero, N. (Noemí); Martínez-Calderón, M. (Miguel); Domke, M. (Matthias); Gómez-Aranzadi, M. (Mikel); Granados-Mateo, E. (Eduardo)We demonstrate a rapid, accurate, and convenient method for tailoring the optical properties of diamond surfaces by employing laser induced periodic surface structuring (LIPSSs). The characteristics of the fabricated photonic surfaces were adjusted by tuning the laser wavelength, number of impinging pulses, angle of incidence and polarization state. Using Finite Difference Time Domain (FDTD) modeling, the optical transmissivity and bandwidth was calculated for each fabricated LIPSSs morphology. The highest transmission of ~99.5% was obtained in the near-IR for LIPSSs structures with aspect ratios of the order of ~0.65. The present technique enabled us to identify the main laser parameters involved in the machining process, and to control it with a high degree of accuracy in terms of structure periodicity, morphology and aspect ratio. We also demonstrate and study the conditions for fabricating spatially coherent nanostructures over large areas maintaining a high degree of nanostructure repeatability and optical performance. While our experimental demonstrations have been mainly focused on diamond anti-reflection coatings and gratings, the technique can be easily extended to other materials and applications, such as integrated photonic devices, high power diamond optics, or the construction of photonic surfaces with tailored characteristics in general.
- Polarization conversion on nanostructured metallic surfaces fabricated by LIPSS(SPIE, 2019) Olaizola, S.M. (Santiago Miguel); Perez-Hernandez, N. (Noemí); Casquero, N. (Noemí); Martínez-Calderón, M. (Miguel); Rodríguez, A. (Ainara); Granados-Mateo, E. (Eduardo)Waveplates modify polarization by generating a phase change. Laser Induced Periodic Surface Structures (LIPSS) have recently started to be studied as waveplates due to the birefringence in-duced by the nanoripples, easily fabricated in a one-step process by laser, where LIPSS morphology is defined by the characteristics of the laser process parameters and the substrate material. The optical properties of these waveplates are defined by LIPSS parameters such as period, depth or width of the ripples. In this work we have deposited thin film coatings on stainless steel samples containing LIPSS for different coating thickness and composition. Results show that thin film coatings are a good candidate for the tunability of LIPSS birefringence since the coating modifies the induced polarization change and reflectivity of the sample depending on coating thickness and composition, as expected from numerical simulations.