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Journal: Applied Optics

Paper: Normalization of laser-induced breakdown spectroscopy spectra using a plastic optical fiber light collector and acoustic sensor device

AUTHORS: Francisco Anabitarte, Luis Rodríguez-Cobo, José Miguel López-Higuera, Adolfo Cobo

Abstract: To estimate the acoustic plasma energy in laser-induced breakdown spectroscopy (LIBS) experiments, a light collecting and acoustic sensing device based on a coil of plastic optical fiber (POF) is proposed. The speckle perturbation induced by the plasma acoustic energy was monitored using a CCD camera placed at the end of a coil of multimode POF and processed with an intraimage contrast ratio method. The results were successfully verified with the acoustic energy measured by a reference microphone. The proposed device is useful for normalizing LIBS spectra, enabling a better estimation of the sample’s chemical composition
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Journal: IEEE Sensors Journal

Paper: Sensor system based on a Brillouin fiber laser for remote in series fiber Bragg gratings interrogation  

AUTHORS: A. Ullan, M.A. Quintela, L. Rodriguez-Cobo, A. Quintela y J.M. Lopez-Higuera 

Abstract: A simple sensor system designed to monitor the temperature or strain of a certain number of critical points along a structure is presented and demonstrated. It is based on the remote interrogation of fiber Bragg gratings placed in series by means of a Brillouin fiber laser. Three FBGs were interrogated at 50 km away from the processing unit using 8 mW of Brillouin pump. Heterodyne detection brings forth a signal to noise ratio of approximately 40 dB in our measurements. 


Journal: Journal of Sensors

Paper: Brillouin Distributed Fiber Sensors: an overview and applications 

AUTHORS: C.A. Galíndez-Jamioy, José Miguel López-Higuera 

Abstract: A review focused on real world applications of Brillouin distributed fiber sensors is presented in this paper. After a brief overview of the theoretical principles, some works to face the two main technical challenges (large dynamic range and higher spatial resolution) are commented. Then an overview of some real and on-field applications is done. 


Journal: Optics Express

Paper: 'Development and integration of xerogel polymeric absorbance micro-filters into lab-onchip systems

AUTHORS: Ester Carregal-Romero, César Fernández-Sánchez, Alma Eguizabal, Stefanie Demming, Stephanus Büttgenbach and Andreu Llobera

Abstract: This work reports on the implementation of different absorption micro-filters based on a dye-doped hybrid organic-inorganic xerogel polymeric material synthesized by the sol-gel process. Microstructures containing eight different filter widths were fabricated in polydimethylsiloxane (PDMS), bonded to glass substrates and filled with the corresponding dye doped polymeric material by a soft lithography approach. The filtering capacity as a function of dye concentration and filter width was studied and revealed a linear dependence with both parameters, as expected according to the Beer-Lambert law. Zero passband transmittance values and relatively sharp stopband regions were achieved with all the filters, also showing rejection levels between 6 dB and 55 dB. Finally, such filters were monolithically integrated into a disposable fluorescence-based photonic lab-on-a-chip (PhLoC) approach. Calibration curves carried out with a model fluorophore target analyte showed an over two-fold increase in sensitivity and a thirty-fold decrease of the limit of detection (LOD) compared with the values recorded using the same PhLoC system but without the polymeric filter structure. The results presented herein clearly indicate the feasibility of these xerogel-based absorbance filtering structures for being applied as low-cost optical components that can be easily incorporated into disposable fluorescence-based photonic lab on a chip systems. 

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