Adrian Carbajal | Universidad Juárez Autónoma de Tabasco (original) (raw)

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Papers by Adrian Carbajal

This paper presents an estimate of the land area affected in the event of sea level rise of 0.6 m... more This paper presents an estimate of the land area affected in the event of sea level rise of 0.6 m, 1 m and 2 m for Mexican sates with coasts along Gulf of Mexico. Likewise, the number of residents in vulnerable areas that would occur in the scenario of sea level rise of 1 m is estimated. To do so, terrain elevation data of NASA's Shuttle Radar Topography Mission is used, along with a proprietary algorithm that allows the reconstruction of the affected area. In order to estimate the land area digital image processing is used. These results are geo-referenced for comparison with human settlements in the regions of interest. Results show that the total affected area corresponds to 1.26% of Mexico national territorial extension and 3.18% of the Mexico total population. 174 settlements with 1000 inhabitants or more are expected to be affected. The Mexican state with the largest area affected is Tabasco with more than 21% of its territory, while the most vulnerable population will be Veracruz, with more than 1 million people at risk if the scenario 1m increase would appear today. Meanwhile, 81.1% Quintana Roo population will be at zones with high flood risk. Vulnerable settlements are listed and the maps corresponding to different Mexican states are shown.

Atmospheric conditions change throughout the day, from turbulence to convective conditions depend... more Atmospheric conditions change throughout the day, from turbulence to convective conditions depending on solar irradiation and soil temperature. It is a necessity for optical telecommunications technologies to study propagation of partially coherent beams under convective atmospheric conditions because these are predominant during daytime in tropical regions. In this work, a theoretical and experimental study of the propagation of partially coherent J0 Bessel beams trough a convective medium is presented. Experimental results show that phase singularities are preserved.

In this work we discuss how to correctly obtain the number of degrees of freedom of a system cons... more In this work we discuss how to correctly obtain the number of degrees of freedom of a system constituted by n particles with fixed relative distances and which are immerse in a three-dimensional space. As a result of our analysis, we develop expressions which yield the number of degrees of freedom of an analogous system, not only in three, but in any arbitrary number D of dimensions.

t is a known fact that near field diffraction or Fresnel diffraction calculations are difficult t... more t is a known fact that near field diffraction or Fresnel diffraction calculations are difficult to perform exactly. It is in general necessary to make some approximations in order to obtain a more suitable form. In this work, a numerical implementation based on angular spectrum theory for near field diffraction is presented. The method uses Fast Fourier Transforms (FFT) and it turns out to be accurate and fast. In order to show the capabilities of the method, diffraction near field for a circular aperture and a spiral slit are studied. Numerical and experimental results are shown. This method could be useful to implement pc based physical optics learning.

Journal of The Optical Society of America, 2004

The synthesis of diffraction-free fields with different profiles is described. The synthesis is d... more The synthesis of diffraction-free fields with different profiles is described. The synthesis is done by illuminating a screen containing a circular slit with a cosine beam. The treatment is equivalent to the modulation of the slit transfer characteristics and makes possible a tunable interference interaction of Bessel beams with noncommon axes. These results are generalized, and it is shown that coherent diffraction-free fields with arbitrary profiles can be expressed as the superposition of shifted zero-order Bessel beams and temporary parametric representations of the shifted functions. Diffraction-free fields with partially coherent features can be obtained. Experimental results are shown for each case.

Optics Express, 2010

An alternative method to generate J0 Bessel beams with controlled spatial partial coherence prope... more An alternative method to generate J0 Bessel beams with controlled spatial partial coherence properties is introduced. Far field diffraction from a discrete number of source points on an annular region is calculated. The average for different diffracted fields produced at several rotation angles is numerically calculated and experimentally detected. Theoretical and experimental results show that for this particular case, J0 Bessel beam is a limit when the number of points tends towards infinity and the associated complex degree of coherence is also a function of the number of points.

Optics Communications, 2006

Coherence is the study of the amplitude correlations of optical fields. Its physical features can... more Coherence is the study of the amplitude correlations of optical fields. Its physical features can be obtained from the cross-spectral density function W( x1, x2, γ) which satisfies two coupled Helmholtz equations. In this article, we describe the amplitude of the optical field using the angular spectrum model. With this representation we calculate the propagation of the correlation function emerging from a transmittance plane. We show that the cross-spectral density function, can be described by just one Helmholtz equation. The treatment permits us to associate directional features to the coherence phenomena. This implies the existence of extremal trajectories of correlation, which are characterized by an eikonal equation, and the existence of a function for media fluctuations, which we term the correlation refractive index. Experimental results are shown for the synthesis of partially coherent focusing regions, which are described by an ensemble of extreme correlation trajectories.

Optics Communications, 2006

Coherence is the study of the amplitude correlations of optical fields. Its physical features can... more Coherence is the study of the amplitude correlations of optical fields. Its physical features can be obtained from the cross-spectral density function W(x1,x2,gamma) which satisfies two coupled Helmholtz equations. In this article, we describe the amplitude of the optical field using the angular spectrum model. With this representation we calculate the propagation of the correlation function emerging from a transmittance

Optics Communications, 2008

We describe the synthesis of diffraction free beams and dark hollow beams with features easily tu... more We describe the synthesis of diffraction free beams and dark hollow beams with features easily tunable using a holographic transmittance. The hologram is generated by interfering two zero order Bessel beams with non-common axis. Spatial filtering techniques are implemented by controlling the illumination during the reconstruction process. The experimental results are for illumination similar to the one used in the recording process, obtaining a set of diffracting free beams. One of these beams propagates quasi-parallel to the surface hologram. For illumination with a plane wave we obtain a dark hollow beam propagating in the same direction as the reconstructions beam. Experimental results are shown in both cases.

Journal of The European Optical Society-rapid Publications, 2011

Elementary long-range plasmon modes are described assuming an exponential dependence of the refra... more Elementary long-range plasmon modes are described assuming an exponential dependence of the refractive index in the neighbourhood of the interface dielectric-metal thin film. The study is performed using coupling mode theory. The interference between two long-range plasmon modes generated that way allows the synthesis of surface sinusoidal plasmon modes, which can be considered as completely coherent generalized plasmon modes. These sinusoidal plasmon modes are used for the synthesis of new partially coherent surface plasmon modes, which are obtained by means of an incoherent superposition of sinusoidal plasmon modes where the period of each one is considered as a random variable. The kinds of surface modes generated have an easily tuneable profile controlled by means of the probability density function associated to the period. We show that partially coherent plasmon modes have the remarkable property to control the length of propagation which is a notable feature respect to the completely coherent surface plasmon mode. The numerical simulation for sinusoidal, Bessel, Gaussian and Dark Hollow plasmon modes are presented.

This paper presents an estimate of the land area affected in the event of sea level rise of 0.6 m... more This paper presents an estimate of the land area affected in the event of sea level rise of 0.6 m, 1 m and 2 m for Mexican sates with coasts along Gulf of Mexico. Likewise, the number of residents in vulnerable areas that would occur in the scenario of sea level rise of 1 m is estimated. To do so, terrain elevation data of NASA's Shuttle Radar Topography Mission is used, along with a proprietary algorithm that allows the reconstruction of the affected area. In order to estimate the land area digital image processing is used. These results are geo-referenced for comparison with human settlements in the regions of interest. Results show that the total affected area corresponds to 1.26% of Mexico national territorial extension and 3.18% of the Mexico total population. 174 settlements with 1000 inhabitants or more are expected to be affected. The Mexican state with the largest area affected is Tabasco with more than 21% of its territory, while the most vulnerable population will be Veracruz, with more than 1 million people at risk if the scenario 1m increase would appear today. Meanwhile, 81.1% Quintana Roo population will be at zones with high flood risk. Vulnerable settlements are listed and the maps corresponding to different Mexican states are shown.

Atmospheric conditions change throughout the day, from turbulence to convective conditions depend... more Atmospheric conditions change throughout the day, from turbulence to convective conditions depending on solar irradiation and soil temperature. It is a necessity for optical telecommunications technologies to study propagation of partially coherent beams under convective atmospheric conditions because these are predominant during daytime in tropical regions. In this work, a theoretical and experimental study of the propagation of partially coherent J0 Bessel beams trough a convective medium is presented. Experimental results show that phase singularities are preserved.

In this work we discuss how to correctly obtain the number of degrees of freedom of a system cons... more In this work we discuss how to correctly obtain the number of degrees of freedom of a system constituted by n particles with fixed relative distances and which are immerse in a three-dimensional space. As a result of our analysis, we develop expressions which yield the number of degrees of freedom of an analogous system, not only in three, but in any arbitrary number D of dimensions.

t is a known fact that near field diffraction or Fresnel diffraction calculations are difficult t... more t is a known fact that near field diffraction or Fresnel diffraction calculations are difficult to perform exactly. It is in general necessary to make some approximations in order to obtain a more suitable form. In this work, a numerical implementation based on angular spectrum theory for near field diffraction is presented. The method uses Fast Fourier Transforms (FFT) and it turns out to be accurate and fast. In order to show the capabilities of the method, diffraction near field for a circular aperture and a spiral slit are studied. Numerical and experimental results are shown. This method could be useful to implement pc based physical optics learning.

Journal of The Optical Society of America, 2004

The synthesis of diffraction-free fields with different profiles is described. The synthesis is d... more The synthesis of diffraction-free fields with different profiles is described. The synthesis is done by illuminating a screen containing a circular slit with a cosine beam. The treatment is equivalent to the modulation of the slit transfer characteristics and makes possible a tunable interference interaction of Bessel beams with noncommon axes. These results are generalized, and it is shown that coherent diffraction-free fields with arbitrary profiles can be expressed as the superposition of shifted zero-order Bessel beams and temporary parametric representations of the shifted functions. Diffraction-free fields with partially coherent features can be obtained. Experimental results are shown for each case.

Optics Express, 2010

An alternative method to generate J0 Bessel beams with controlled spatial partial coherence prope... more An alternative method to generate J0 Bessel beams with controlled spatial partial coherence properties is introduced. Far field diffraction from a discrete number of source points on an annular region is calculated. The average for different diffracted fields produced at several rotation angles is numerically calculated and experimentally detected. Theoretical and experimental results show that for this particular case, J0 Bessel beam is a limit when the number of points tends towards infinity and the associated complex degree of coherence is also a function of the number of points.

Optics Communications, 2006

Coherence is the study of the amplitude correlations of optical fields. Its physical features can... more Coherence is the study of the amplitude correlations of optical fields. Its physical features can be obtained from the cross-spectral density function W( x1, x2, γ) which satisfies two coupled Helmholtz equations. In this article, we describe the amplitude of the optical field using the angular spectrum model. With this representation we calculate the propagation of the correlation function emerging from a transmittance plane. We show that the cross-spectral density function, can be described by just one Helmholtz equation. The treatment permits us to associate directional features to the coherence phenomena. This implies the existence of extremal trajectories of correlation, which are characterized by an eikonal equation, and the existence of a function for media fluctuations, which we term the correlation refractive index. Experimental results are shown for the synthesis of partially coherent focusing regions, which are described by an ensemble of extreme correlation trajectories.

Optics Communications, 2006

Coherence is the study of the amplitude correlations of optical fields. Its physical features can... more Coherence is the study of the amplitude correlations of optical fields. Its physical features can be obtained from the cross-spectral density function W(x1,x2,gamma) which satisfies two coupled Helmholtz equations. In this article, we describe the amplitude of the optical field using the angular spectrum model. With this representation we calculate the propagation of the correlation function emerging from a transmittance

Optics Communications, 2008

We describe the synthesis of diffraction free beams and dark hollow beams with features easily tu... more We describe the synthesis of diffraction free beams and dark hollow beams with features easily tunable using a holographic transmittance. The hologram is generated by interfering two zero order Bessel beams with non-common axis. Spatial filtering techniques are implemented by controlling the illumination during the reconstruction process. The experimental results are for illumination similar to the one used in the recording process, obtaining a set of diffracting free beams. One of these beams propagates quasi-parallel to the surface hologram. For illumination with a plane wave we obtain a dark hollow beam propagating in the same direction as the reconstructions beam. Experimental results are shown in both cases.

Journal of The European Optical Society-rapid Publications, 2011

Elementary long-range plasmon modes are described assuming an exponential dependence of the refra... more Elementary long-range plasmon modes are described assuming an exponential dependence of the refractive index in the neighbourhood of the interface dielectric-metal thin film. The study is performed using coupling mode theory. The interference between two long-range plasmon modes generated that way allows the synthesis of surface sinusoidal plasmon modes, which can be considered as completely coherent generalized plasmon modes. These sinusoidal plasmon modes are used for the synthesis of new partially coherent surface plasmon modes, which are obtained by means of an incoherent superposition of sinusoidal plasmon modes where the period of each one is considered as a random variable. The kinds of surface modes generated have an easily tuneable profile controlled by means of the probability density function associated to the period. We show that partially coherent plasmon modes have the remarkable property to control the length of propagation which is a notable feature respect to the completely coherent surface plasmon mode. The numerical simulation for sinusoidal, Bessel, Gaussian and Dark Hollow plasmon modes are presented.