Person: Alda Serrano, Javier
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First Name
Javier
Last Name
Alda Serrano
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Department
Óptica
Area
Optica
Identifiers
5 results
Search Results
Now showing 1 - 5 of 5
Item Gold-coated split laser-induced periodic surface structures as refractometric sensors(Optics and Laser Technology, 2022) San Blas, Alejandro; Elshorbagy, Mahmoud Hamdy Mohamed; Olaizola Izquierdo, Santiago M.; Sánchez Brea, Luis Miguel; Rodríguez González, Ainara; Del Hoyo Muñoz, Jesús; Granados, Eduardo; Soria García, Ángela; Pastor Villarrubia, Verónica; Alda Serrano, JavierThe generation of surface plasmon resonances (SPR) in laser-induced periodic surface structures (LIPSS) allows their application in the field of optical sensing, such as the detection of refractive index variations in gases and liquids. We have fabricated gold-coated LIPSS nanostructures on stainless steel substrates by using femtosecond laser nano-ablation. This technique is a low-cost and high-throughput fabrication method applicable to fast and large-scale manufacturing. The depth profile of the fabricated LIPSS shows a central dip at the top of each ripple that split the geometry. The actual topography is modeled and included in a computational electromagnetism package to obtain the expected optical response under the experimental conditions. The measured and simulated spectral reflectances are compared, and the differences are explained by the departure of the fabricated LIPSS from the ideal topography. The experiments and simulations showed excellent agreement for the main spectral characteristics, like the Fano-like lineshapes of the spectral reflectance. This fitting provides the values used to determine the refractometric performance of the fabricated device, that shows a sensitivity of 518 nm/RIU and a figure of merit of 32 RIU−1 for an aqueous analyte. Our experimental results show that the fabricated devices are competitive in terms of cost and simplicity when compared to existing devices with similar performance.Item Stokes polarimeter using vector diffractive optical elements(2023) Soria García, Ángela; Del Hoyo Muñoz, Jesús; Sánchez Brea, Luis Miguel; Pastor Villarrubia, Verónica; González Fernández, Verónica; Elshorbagy, Mahmoud H.; Alda Serrano, JavierWe designed, fabricated and tested a Vector Diffractive Optical Element (VDOE) to simultaneously determine the Stokes vector of light. It comprises several sectors. Each one is a vector Fresnel zone plate which focuses the light on separate foci and has different polarization properties. The polarization state is calculated from their intensities. From simulations, we could identify the error sources that were analytically removed. The residual uncertainty after applying our corrections was as low as 6x10^(-5). The uncertainty obtained for our fabricated VDOE, 3.33 %, is competitive with the results from state-of-the-art techniques.Item Fabrication effects in the optical performance of DOEs engraved with femtosecond lasers(Proceedings of SPIE, 2021) Soria García, Ángela; Fantova, Jorge; San Blas, Alejandro; Hoyo Muñoz, Jesús del; Sánchez Brea, Luis Miguel; Alda Serrano, Javier; Rodríguez González, Ainara; Olaizola Izquierdo, Santiago M.The development of DOEs fabrication techniques is continuously growing due to the wide range of industrial applications, such as beam manipulation or optical position encoders. In this work, we use Femtosecond laser direct writing to manufacture DOEs, which uses a simpler and more efficient way to fabricate amplitude binary masks. Also, we have analyzed the performance of the DOEs. The fabrication technique is validated since the experimental results are in accordance to numerical simulations.Item Permeable Diffractive Optical Elements for the real-time sensing of running fluids(2023) Pastor Villarrubia, Verónica; Soria García, Ángela; Del Hoyo Muñoz, Jesús; Sánchez Brea, Luis Miguel; Alda Serrano, JavierThe real-time monitoring of physical and chemical parameters in running fluids is of importance for biomedical, biochemical, and environmental applications, such as the presence of biomarkers or chemomarkers, or the departure from some preset values of critical parameters. In this contribution we present a new generation of Permeable Diffractive Optical Elements (PDOE) based on photon sieves. In brief, the PDOE is made of passing holes properly placed on specific locations on a rigid surface. This arrangement makes PDOEs ideal to work with running fluids. Our PDOE is optimized maximizing the irradiance at is focal plane, maintaining an appropriate permeability ratio. The starting point is the classical Fresnel zone distribution. We have used two different optimization strategies to design a working PDOE: i) Particle Swarm Optimization has been applied to modify the distribution of holes on the PDOE simultaneously considering all of them; ii) an iterative minimization algorithm adding one hole at the time until filling the PDOE aperture. Both optimization algorithms generate focal spots that are compared to choose the design better suited for the proposed application. Once the PDOE is optimized and fabricated, the surface of the remaining rigid structure is nanostructured (for example using Laser Induced Periodic Surface Structures), or functionalized, to provide specific sensing capabilities. In addition, the PDOE is integrated within a pipe where the fluid under analysis circulates through. A proposal for the optoelectronic assembly of the device-including auxiliary optical elements, light sources, and detectors - is also presented in this contribution.Item Interferometric method for simultaneous characterization of retardance and fast axis of a retarder(Optics and Lasers in Engineering, 2024) Del Hoyo Muñoz, Jesús; Porras, Joaquin Andres; Soria García, Ángela; Sánchez Brea, Luis Miguel; Pastor Villarrubia, Veronica; Hamdy Mohamed Elshorbagy, Mahmoud; Alda Serrano, JavierIn this work, we propose a technique to simultaneously measure the absolute retardance and the fast axis azimuth of a retarder using a Michelson interferometer with polarization control. One of the mirrors is slightly tilted to obtain interference fringes with collimated beams. The sample to measure is rotated and the parameters are obtained from the fringes displacement. The technique does not require the use of additional previously characterized retarders in the measurement process, but only linear polarizers. The experimental results present errors of the order of 2◦ for the retardance and 1◦ for the azimuth of the fast axis.