Browsing by Author "Garcia-Merino, J. A."

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    Laser ablation fingerprint in low crystalline carbon nanotubes: A structural and photothermal analysis
    (2024) Garcia-Merino, J. A.; Villarroel, R.; Chavez-Angel, E.; Hevia, S. A.
    Carbon nanotubes (CNT) hold promise as photothermal materials due to their cost-effectiveness, stability, and broad optical absorbance. Here, we investigate the structural and morphological modifications in low-crystalline vertically aligned CNT synthetized via chemical vapor deposition on n-type Si substrates at 750 degrees C, followed by annealing treatment with near-infrared laser radiation. Raman spectroscopy revealed laser-induced amorphous regions, facilitating identification of ablation thresholds. Time-dependent nonlinear photothermal emission, associated with CNT ablation, showed a stable thermodynamic equilibrium with broad-band radiation from an electron-hole plasma. We propose a model based on Raman spectra and positional scans of the ablation fingerprint, enabling correlation with the beam temperature profile. This study offers insights into laser beam characterization, with potential applications in plasma and optics disciplines.
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    Magnetic frequency identification by quantum interference in magnetoplasmonic carbon/metal nanostructures
    (2021) Garcia-Merino, J. A.; Mercado-Zuniga, C.; Hernandez-Acosta, M. A.; Aguilar-Perez, L. A.; Villanueva-Fierro, I.; Hevia, S. A.; Torres-Torres, C.
    The frequency of an alternating magnetic field acting on multiwall carbon nanotubes decorated with Pt nanoparticles was identified as a change in conductance. The samples were prepared in film form using chemical vapor deposition and Pt nanoparticles were grown with acid precursors. Sample characterizations were analyzed by transmission and scanning electron microscopies. In a conductance dependent temperature measurement, the sample exhibits a non-metallic behavior. A Bode analysis shows a relocation on the controllable poles in the magneto-conductive activity. Moreover, optical nonlinearities were studied by single-beam and two-wave mixing configurations in the nanosecond regime. The optical absorbance dependent on irradiance and magnetic field was analytically described. Significant changes in two-wave mixing experiment were observed by magnetic perturbation. Sensitive magnetoplasmonic interactions by adding Pt nanoparticles on carbon nanotubes were responsible for enhancing magnetic and nonlinear optical effects. Immediate applications for scalable magnetophotonic systems in quantum sensing can be contemplated.