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J. J. Sánchez-Mondragón

Bio: J. J. Sánchez-Mondragón is an academic researcher from National Institute of Astrophysics, Optics and Electronics. The author has contributed to research in topics: Optical fiber & Photonic crystal. The author has an hindex of 14, co-authored 157 publications receiving 698 citations. Previous affiliations of J. J. Sánchez-Mondragón include Universidad Autónoma del Estado de Morelos & Universidad Autónoma del Estado de México.


Papers
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Journal ArticleDOI

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TL;DR: Experimental results on the propagation of an interference pattern of two He-Ne laser beams of unequal amplitudes through a photorefractive Bi(12)TiO(20) crystal in the presence of drift nonlinearity are presented.
Abstract: We present experimental results on the propagation of an interference pattern of two He–Ne laser beams of unequal amplitudes through a photorefractive Bi12TiO20 crystal in the presence of drift nonlinearity. The phenomenon that we have observed is the focusing of the fringes as the nonlinearity of the crystal is increased. We show that such a phenomenon can be quantitatively interpreted in the framework of modulation instability theory.

53 citations

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TL;DR: In this paper, the spectral transmission response of a long-period holey fiber grating mechanically induced in two different twisted holey fibers was investigated and it was shown that each resonance wavelength of the grating splits when the fiber is twisted prior pressure application, and the new upper and lower resonance wavelengths show an opposite symmetrical shift that increases proportionally with the induced twist ratio.
Abstract: We present the spectral transmission response of a long-period holey fiber grating mechanically induced in two different twisted holey fibers. We have found that each resonance wavelength of the grating splits when the holey fiber is twisted prior pressure application. The new upper and lower resonance wavelengths show an opposite symmetrical shift that increases proportionally with the induced twist ratio, and it does not depend on tuning and twist direction. The shift observed in the splitting of the peaks in the mechanically induced long-period holey fiber grating is higher than that obtained in standard single-mode fibers and its sensitivity depends of the transverse structure of the holey fiber. High sensitivity is observed in the fiber with asymmetrical cladding structure. These results are important in the design of new torsion sensors based in long-period holey fiber gratings.

39 citations

Proceedings ArticleDOI

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13 Nov 2006
TL;DR: An automatic method to obtain cells detection and cells migration tracking in order to analyze cells behaviors under different conditions using phase-contrast video microscopy method is proposed.
Abstract: In this paper, we propose an automatic method to obtain cells detection and cells migration tracking in order to analyze cells behaviors under different conditions. The images were obtained using phase-contrast video microscopy method. Proposed method normalizes original images in order to increase image contrast, and a classification process based on variance operator determines the nature of pixels in the image as cells or background. Each detected cell is associated to its centroid in order to initialize the tracking procedure to quantify the migration process. This technique is a fast way to describe cells migrations, robust to cell contracts and mitosis, all over their trajectories.

34 citations

Journal ArticleDOI

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TL;DR: By direct interferometric measurement in Bi 12 TiO 20 under external DC electric field, the steady-state photorefractive lens produced by the laser beam with the initial circular cross-section is essentially anisotropic: its focusing strength along the direction of the applied electric field is remarkably higher as mentioned in this paper.
Abstract: By direct interferometric measurement in Bi 12 TiO 20 under external DC electric field, we demonstrate that the steady-state photorefractive lens produced by the laser beam with the initial circular cross-section is essentially anisotropic: its focusing strength along the direction of the applied electric field is remarkably higher. Experimental data are supported by computer simulations and analytical results.

28 citations

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01 Jan 2011
TL;DR: In this article, a temperature sensor based on multimode interference was designed, fabricated and tested, which is very simple and inexpensive since we only need to splice a section of multimode fiber between two single mode fibers.
Abstract: A novel fiber optic temperature sensor based on multimode interference was designed, fabricated and tested. The sensor is very simple and inexpensive since we only need to splice a section of multimode fiber between two single mode fibers. Using this device a sensing range of 25°C to 375°C is demonstrated. We should also highlight that due to the pass-band filter response of MMI devices, multiplexing is rather simple by just changing the length of the multimode section.

26 citations


Cited by
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Journal Article

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TL;DR: In this article, a fast Fourier transform method of topography and interferometry is proposed to discriminate between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour generation techniques.
Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

3,742 citations

Journal ArticleDOI

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01 Mar 2002-Science
TL;DR: A method to generate steady coaxial jets of immiscible liquids with diameters in the range of micrometer/nanometer size is reported, which has produced monodisperse capsules with diameter varying between 10 and 0.15 micrometers, depending on the running parameters.
Abstract: We report a method to generate steady coaxial jets of immiscible liquids with diameters in the range of micrometer/nanometer size. This compound jet is generated by the action of electro-hydrodynamic (EHD) forces with a diameter that ranges from tens of nanometers to tens of micrometers. The eventual jet breakup results in an aerosol of monodisperse compound droplets with the outer liquid surrounding or encapsulating the inner one. Following this approach, we have produced monodisperse capsules with diameters varying between 10 and 0.15 micrometers, depending on the running parameters.

931 citations

Book ChapterDOI

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27 Jan 2010

878 citations

Journal ArticleDOI

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TL;DR: In this paper, the real variable is replaced by a complex variable, and the factorial and related functions of the complex variable are used to solve linear differential equations of the second order.
Abstract: 1. The real variable 2. Scalars and vectors 3. Tensors 4. Matrices 5. Multiple integrals 6. Potential theory 7. Operational methods 8. Physical applications of the operational method 9. Numerical methods 10. Calculus of variations 11. Functions of a complex variable 12. Contour integration and Bromwich's integral 13. Contour integration 14. Fourier's theorem 15. The factorial and related functions 16. Solution of linear differential equations of the second order 17. Asymptotic expansions 18. The equations of potential, waves and heat conduction 19. Waves in one dimension and waves with spherical symmetry 20. Conduction of heat in one and three dimensions 21. Bessel functions 22. Applications of Bessel functions 23. The confluent hypergeometric function 24. Legendre functions and associated functions 25. Elliptic functions Notes Appendix on notation Index.

771 citations

Journal ArticleDOI

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TL;DR: In this paper, an experimental single stage heat transformer (SSHT) with water/carrol mixture was analyzed. But the performance of the SSHT was not evaluated. But four test runs were carried out in order to evaluate the performance and the heat powers were measured from 0.99 to 1.35.
Abstract: Single Stage Heat Transformer (SSHT) is a device to recovery waste heat by a thermodynamic cycle. In this paper an experimental SSHT prototype was analyzed. This prototype operates with Water/Carrol mixture. Four test runs were carried out in order to evaluate the performance. The heat powers were measured from 0.99 to 1.35 kW for the generator, 0.97–1.33 kW for the condenser, 0.99–1.35 kW for the evaporator and 0.69–0.81 kW for the absorber. Experimental Gross Temperature Lift (GTL) was values from 18.5 to 22.2 °C and the dimensionless Coefficient of Performance (COP) was calculated for those operating conditions from 0.30 to 0.35.

720 citations