Prof. Rubén Ramos-García Profile

Prof. Rubén Ramos-García

Doctor/Associate Professor at INAOE

SPIE Involvement:

Conference Program Committee | Author | Student Chapter Advisor

Websites:

Company Website

Publications (67)

Proceedings Article | 4 October 2024 Poster + Paper

Tunable nanostructuring of glass substrates using cost-effective nanopatterning techniques

I. Gazga-Gurrión, A.-M. Ruiz-Ramirez, R. Lugo, N. Korneev, R. Ramos-García, S. Mansurova

Proceedings Volume 13116, 131160E (2024) https://doi.org/10.1117/12.3028281

KEYWORDS: Glasses, Nanostructuring, Gold, Film thickness, Reflectivity, Annealing, Solar cells, Optical properties, Scanning electron microscopy, Reflection

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Proceedings Article | 4 October 2024 Poster + Paper

Theoretical modeling of reflectance and scattering properties of nanostructured glass surfaces for solar cells applications

A.-M. Ruiz-Ramírez, J. Cuanalo-Fernández, R. Ramos-García, S. Mansurova

Proceedings Volume 13116, 131160F (2024) https://doi.org/10.1117/12.3028304

KEYWORDS: Reflectivity, Glasses, Analytic models, Optical spheres, Particles, Nanostructuring, Scattering, Physical coherence, Reflection, Monolayers

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Proceedings Article | 2 October 2024 Poster + Paper

Optical tweezers reveal increased intracellular viscosity in Candida tropicalis after APDT

D. Carranza-Zuñiga, J. Ascencio-Rodríguez, T. Spezzia-Mazzocco, R. Ramos-García

Proceedings Volume 13112, 131120E (2024) https://doi.org/10.1117/12.3028178

KEYWORDS: Viscosity, Optical tweezers, Cell death, Yeast, Switching, Biofilms, Photodynamic therapy

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SPIE Journal Paper | 5 December 2023 Open Access

Improved spatial speckle contrast model for tissue blood flow imaging: effects of spatial correlation among neighboring camera pixels

Julio Cesar Juarez-Ramirez, Beatriz Coyotl-Ocelotl, Bernard Choi, Ruben Ramos-Garcia, Teresita Spezzia-Mazzocco, Julio C. Ramirez-San-Juan

JBO, Vol. 28, Issue 12, 125002, (December 2023) https://doi.org/10.1117/12.10.1117/1.JBO.28.12.125002

KEYWORDS: Speckle, Windows, Blood circulation, Tissues, Cameras, Speckle pattern, Data modeling, Laser speckle contrast imaging, Mathematical modeling, Autocorrelation

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Proceedings Article | 5 October 2023 Presentation + Paper

Generation, 3D trapping, and self-oscillation microbubbles

J. Pérez-Corte, J. Sarabia-Alonso, J. Ortega-Mendoza, K. Ortega-Sánchez, R. Ramos-García

Proceedings Volume 12649, 126490I (2023) https://doi.org/10.1117/12.2676019

KEYWORDS: Bubbles, Bioalcohols, Liquids, Near infrared, Light absorption, Temperature distribution, Continuous wave operation, Viscosity, Temperature metrology, Optical tweezers

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Proceedings Article | 5 October 2023 Poster + Paper

Topological darkness in random gold metasurfaces for high sensitivity detection using phase interrogation

J. Cuanalo-Fernández, N. Korneev, I. Cosme-Bolaños, M. de la Mora, I. Gazga-Gurrion, S. Mansurova, R. Ramos-García

Proceedings Volume 12648, 126480E (2023) https://doi.org/10.1117/12.2676565

KEYWORDS: Gold, Reflectivity, Polarization, Plasmonics, Refractive index, Nanostructures, Reflection, Localized surface plasmon resonances, Optical spheres

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Proceedings Article | 5 October 2023 Poster + Paper

Position-sensitive photodetector for plasmonic detection in a random metasurface

Carla Labastida, Juan Cuanalo, Irving Gazga, Rubén Ramos, Svetlana Mansurova, Nikolai Korneev

Proceedings Volume 12648, 126480G (2023) https://doi.org/10.1117/12.2677359

KEYWORDS: Localized surface plasmon resonances, Transducers, Plasmonics, Refractive index, Gold, Signal detection, Photodetectors, Scanning electron microscopy, Glasses, Sensing systems

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Proceedings Article | 5 October 2023 Poster + Paper

Plasmonic response of a random metasurface based on gold nano-islands in attenuated total reflectance configuration

J. Cuanalo-Fernández, I. Gazga-Gurrión, I. Cosme-Bolaños, N. Korneev, R. Lugo, R. Ramos-García, S. Mansurova

Proceedings Volume 12648, 126480H (2023) https://doi.org/10.1117/12.2677728

KEYWORDS: Gold, Plasmonics, Localized surface plasmon resonances, Refractive index, Film thickness, Reflectivity, Scanning electron microscopy, Annealing, Reflection, Thin films

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SPIE Journal Paper | 21 July 2023 Open Access

Bubble dynamics and speed of jets for needle-free injections produced by thermocavitation

Nancy Elizabeth González-Sierra, José Manuel Perez-Corte, Juan Pablo Padilla-Martinez, Samuel Cruz-Vanegas, Silvio Bonfadini, Filippo Storti, Luigino Criante, Rubén Ramos-García

JBO, Vol. 28, Issue 07, 075004, (July 2023) https://doi.org/10.1117/12.10.1117/1.JBO.28.7.075004

KEYWORDS: Bubbles, Skin, Vacuum chambers, Liquids, Nozzles, Pulsed laser operation, Beam diameter, Design and modelling, Laser applications, Water

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SignificanceThe number of injections administered has increased dramatically worldwide due to vaccination campaigns following the COVID-19 pandemic, creating a problem of disposing of syringes and needles. Accidental needle sticks occur among medical and cleaning staff, exposing them to highly contagious diseases, such as hepatitis and human immunodeficiency virus. In addition, needle phobia may prevent adequate treatment. To overcome these problems, we propose a needle-free injector based on thermocavitation.AimExperimentally study the dynamics of vapor bubbles produced by thermocavitation inside a fully buried 3D fused silica chamber and the resulting high-speed jets emerging through a small nozzle made at the top of it. The injected volume can range from ∼0.1 to 2 μL per shot. We also demonstrate that these jets have the ability to penetrate agar skin phantoms and ex-vivo porcine skin.ApproachThrough the use of a high-speed camera, the dynamics of liquid jets ejected from a microfluidic device were studied. Thermocavitation bubbles are generated by a continuous wave laser (1064 nm). The 3D chamber was fabricated by ultra-short pulse laser-assisted chemical etching. Penetration tests are conducted using agar gels (1%, 1.25%, 1.5%, 1.75%, and 2% concentrations) and porcine tissue as a model for human skin.ResultHigh-speed camera video analysis showed that the average maximum bubble wall speed is about 10 to 25 m/s for almost any combination of pump laser parameters; however, a clever design of the chamber and nozzle enables one to obtain jets with an average speed of ∼70 m / s. The expelled volume per shot (0.1 to 2 μl) can be controlled by the pump laser intensity. Our injector can deliver up to 20 shots before chamber refill. Penetration of jets into agar of different concentrations and ex-vivo porcine skin is demonstrated.ConclusionsThe needle-free injectors based on thermocavitation may hold promise for commercial development, due to their cost and compactness.

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Proceedings Article | 3 October 2022 Poster + Paper

3D manipulation of vapor microbubbles driven by the Marangoni force

J. Sarabia-Alonso, J. Ortega-Mendoza, J. Ascencio-Rodríguez, R. Ramos-García

Proceedings Volume 12198, 121980I (2022) https://doi.org/10.1117/12.2634298

KEYWORDS: Optical fibers, Bioalcohols, Absorption, Continuous wave operation, Silver, Fiber lasers, Nanoparticles, Thermography, Optical trapping, Optical manipulation

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Proceedings Article | 14 November 2021 Poster + Paper

2D/3D single-pixel NIR image reconstruction method for outdoor applications in presence of rain

C. Osorio Quero, D. Durini Romero, J. Rangel-Magdaleno, J. Martinez Carranza, R. Ramos-Garcia

Proceedings Volume 11914, 1191415 (2021) https://doi.org/10.1117/12.2601118

KEYWORDS: Reconstruction algorithms, 3D image reconstruction, 3D image processing, Scattering, 3D modeling, Light scattering, Reflectivity, Particles, Mie scattering, Sensors

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In this paper, we propose a method for single-pixel 2D/3D imaging to be applied in hyperspectral cameras operating in outdoor applications in unmanned aerial vehicles (UAVs). In rain rich environments, if camera systems operating in the visible range are used, alongside the atmospheric absorption that inevitably takes place, additional interactions occur between the light to be detected and the raindrops that produce Rayleigh and other scattering effects, thus limiting the visibility of the imagers mainly due to induced limitations in what radiation propagation is concerned. To solve this problem, we follow the approach that consists in using InGaAs based single photodetectors or line sensors that operate in the near-infrared (NIR) part of the spectra, in the wavelength range between 905 nm and 1600 nm. Due to the high costs of the few commercially available InGaAs based image sensors, we propose implementing a vision system based on the principle of single-pixel imaging (SPI) using active NIR illumination as a low-cost solution for image sensors in low-light scattering media. The SPI approach allows for the reconstruction of images from the electrical response signals of single InGaAs photodetectors to impinging active NIR illumination patterns created by an array of NIR LEDs. The latter is enabled by applying compression sensing (CS) algorithms. In this work, we aim at improving the quality of the reconstructed 2D images, defining the SSIM > 0.6 and RMSE<0.3 in rain rich scenarios as goal specifications. This SPI approach is additionally used to generate 3D images by applying Shape-From-Shading (SPS) and improving mesh 3D algorithms. By projecting Hadamard active illumination patterns analyzed in different regions of the reconstructed image, we enable scanning Spiral and Hilbert traces for image reconstruction to improve the SSIM level and reduce RMSE level of the reconstructed 2D/3D image obtained in the presence of rain. For testing purposes, we developed a controlled characterization system that enables rain simulation to evaluate the quality of the reconstructed 2D/3D single-pixel images.

Proceedings Article | 1 August 2021 Poster + Presentation + Paper

Behind optothermal trapping of photothermally-induced microbubbles

J. A. Sarabia-Alonso, J. G. Ortega-Mendoza, J. C. Ramírez-San-Juan, R. Ramos-García

Proceedings Volume 11798, 117982U (2021) https://doi.org/10.1117/12.2594036

KEYWORDS: Bioalcohols, Optical fibers, Absorption, Continuous wave operation, Silver, Fiber lasers, Light, Optical arrays, Nanoparticles, Optical manipulation, Optofluidics, Thermal effects

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Proceedings Article | 20 August 2020 Presentation + Paper

Trapping and manipulation of a microbubble in 3D through temperature gradients

F. M. Muñoz Pérez, J. A. Sarabia-Alonso, A. Padilla-Vivanco, C. Toxqui-Quitl, J. G. Ortega-Mendoza, R. Ramos-García

Proceedings Volume 11463, 1146319 (2020) https://doi.org/10.1117/12.2569829

KEYWORDS: Optical fibers, Absorption, Multimode fibers, Liquids, Single mode fibers, Pulsed laser operation, Continuous wave operation, Temperature metrology, Optical manipulation

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Proceedings Article | 20 August 2020 Poster + Paper

Enhancement of the stiffness constant in optical tweezers by thermal effects

J. Vazquez-Lozano, J. A. Zenteno-Hernández, J. Sarabia-Alonso, J. Ramírez-Ramírez, R. Ramos-García

Proceedings Volume 11463, 1146324 (2020) https://doi.org/10.1117/12.2569571

KEYWORDS: Thermal effects, Optical tweezers, Convection, Thin films, Optical manipulation

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Proceedings Article | 4 May 2020 Presentation + Paper

Hardware parallel architecture proposed to accelerate the orthogonal matching pursuit compressive sensing reconstruction

C. Osorio Quero, D. Durini, R. Ramos-Garcia, J. Rangel-Magdaleno, J. Martinez-Carranza

Proceedings Volume 11396, 113960N (2020) https://doi.org/10.1117/12.2558937

KEYWORDS: Reconstruction algorithms, Image processing, Detection and tracking algorithms, Image restoration, Video acceleration, Video, Compressed sensing, Chemical species, Signal to noise ratio, Signal processing

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The compressive sensing (CS) technique is a novel tool used to reconstruct images using fewer samples, normally sparse in the transform domain, than those required by conventional imaging systems. However, the methods applied for signal reconstruction within the CS approach still present some problems in the implementation, mainly due to their intensive computational demand and high power consumption requirements. These drawbacks need addressing if this approach is followed in systems aimed at e.g. drone autonomous flying or other embedded applications that additionally require very short processing times. In this paper we evaluate the use of hardware based parallel processing architecture for the implementation of the Orthogonal Matching Pursuit (OMP) algorithm, one of the most efficient CS reconstruction algorithms developed so far. To improve the algorithm performance, we target different maximum allowed processing times to reach minimum image resolutions required by each system of interest using different sparse (16 and 64) amounts of single-pixel generated samples per image. We also target the final image resolution to be above 20 dB in terms of the peak signal-to-noise ratio (PSNR). To reduce the execution and processing times required to generate each image, we propose implementing parallel kernels in the hardware platform for each of the operations required by the algorithms under study. In the proposed implementation the reconstructed images are used to generate video streams that form the foundation on which decisions are to be made by the system in continuous time, whereby each single image (frame) reconstruction cannot overcome 30 ms in order to maintain the minimum amount of frames per second (fps) above 33 (minimum required for an acceptable video stream). The implementation of a variation of the OMP algorithm in a graphics processing unit (GPU) using parallel architecture approach allows obtaining processing times 4 or 5 times shorter than those obtained if central processing unit (CPU) based architecture implementation is used for the same purpose.

Proceedings Article | 28 April 2020 Paper

Implementation of a hyperspectral integrated vision system combining radar technology and single-pixel optical principle for unmanned ground vehicles (UGV)

C. Osorio Quero, D. Durini, R. Ramos-García, J. Rangel-Magdaleno, J. Martinez-Carranza, J. L. Olvera, A. Corona

Proceedings Volume 11408, 1140815 (2020) https://doi.org/10.1117/12.2558929

KEYWORDS: Radar, Imaging systems, Photodetectors, Light emitting diodes, Indium gallium arsenide, Orthogonal frequency division multiplexing, Sensors, Near infrared, Spatial resolution, Ranging

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During the last decades the radio detecting and ranging (RADAR) technology underwent an evolution transiting from the linear-frequency-modulated (LFM) systems developed in the 1970s, up to the orthogonal frequency-division multiplexing (OFDM) systems developed in the early 2000s. In mid 2010s, systems were proposed that combined the radar principle with optical solutions developed for imaging and ranging tasks following a hyperspectral embedded systems approach. The idea was to profit on the one side from the possibility offered by RADAR systems to work in harsh environments using emitted radio waves and detect mainly metal objects placed far away (hundreds of meters or even kilometers) from the detection system with positioning spatial resolutions in tens of centimeters, even if there are non-metallic barriers such as e.g. walls in between; and expand this possibility by using optical systems (e.g. light detecting and ranging –LIDAR- systems), using visible light active illumination, capable of generating 2D and 3D images of objects placed at much smaller distances from the detector, but allowing for much higher spatial resolutions (in the millimeter range). To reduce the atmospheric absorption of the emitted active illumination and increase the emitted optical power allowed for these systems that can correctly function even in harsh environments, we propose shifting the active illumination wavelengths from the visible range to the near infra-red (NIR) range, e.g. to 1550 nm. Lacking affordable image sensors fabricated in InGaAs technology, capable of detecting NIR radiation, in this paper we propose a hyperspectral imaging system using a very low power consuming single commercially available InGaAs photodiode to generate 2D images using the single-pixel imaging (SPI) approach based on compressive sensing (CS) and an array of NIR light emitting LEDs, combined with an 80 GHz millimeter band RADAR. The system is conceived to deliver a maximum radar range of 150 m with a maximum spatial resolution of ≤ 5 cm and a RADAR cross-section (RCS) of 10 – 50 m², combined with an optical system capable of generating 24 fps video streams based on SPI generated images yielding a maximum ranging depth of 10 m with a spatial resolution of < 1 cm. The proposed system will be used in unmanned ground vehicle (UGV) applications enabling decision making in continuous time. The power consumption, dimensions and weight of the hyperspectral ranging system will be adjusted to the UGV targeted applications.

Proceedings Article | 27 April 2020 Paper

Evaluation of a 3D imaging vision system based on a single-pixel InGaAs detector and the time-of-flight principle for drones

C. Osorio Quero, D. Durini, R. Ramos-Garcia, J. Rangel-Magdaleno, J. Martinez-Carranza

Proceedings Volume 11402, 114020T (2020) https://doi.org/10.1117/12.2558918

KEYWORDS: Distance measurement, Indium gallium arsenide, Imaging systems, Near infrared, Photodiodes, Sensors, Image processing, Photodetectors, Spatial resolution, Light emitting diodes

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Proceedings Article | 9 September 2019 Presentation + Paper

Colloidal crystal formation using optothermal forces

J. Ramírez-Ramírez, J. Vazquez-Lozano, H. Peregrina-Barreto, R. Ramos-García

Proceedings Volume 11083, 110832H (2019) https://doi.org/10.1117/12.2530312

KEYWORDS: Crystals, Particles, Photonic crystals, Laser crystals, Titanium, Optical tweezers, Microscopes, Convection, Thermal effects, Nanolithography

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Proceedings Article | 9 September 2019 Paper

3D manipulation of microbubbles by laser-induced thermal gradients

J. A. Sarabia-Alonso, J. O. Ortega-Mendoza, J. C. Ramírez-San-Juan, P. Zaca-Morán, A. Padilla-Vivanco, J. Ramírez-Ramírez, R. Ramos-García

Proceedings Volume 11083, 110832X (2019) https://doi.org/10.1117/12.2528549

KEYWORDS: Optical fibers, Pulsed laser operation, Bioalcohols, Liquids, Fiber lasers, Silver, Nanoparticles, Thin films, Absorption, Cavitation

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Proceedings Article | 7 August 2019 Paper

Rose bengal as a photosensitizer in the photodynamic therapy of breast cancer cell lines

JC Atenco-Cuautle, MG Delgado-López, R. Ramos-García, JC Ramírez-San-Juan, J. Ramirez-Ramirez, T. Spezzia-Mazzocco

Proceedings Volume 11070, 11070A1 (2019) https://doi.org/10.1117/12.2525456

KEYWORDS: Photodynamic therapy, Breast cancer, Cancer, Receptors, Absorbance, In vitro testing

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Proceedings Article | 7 August 2019 Paper

Methylene blue as a photosensitizer in the photodynamic therapy of breast cancer cell lines

JC Atenco-Cuautle, T. Spezzia-Mazzocco, R. Ramos-Garcia, JC Ramirez-San-Juan, J. Ramirez-Ramirez, MG Delgado-Lopez

Proceedings Volume 11070, 11070A0 (2019) https://doi.org/10.1117/12.2525454

KEYWORDS: Photodynamic therapy, Breast cancer, Picosecond phenomena, Toxicity, Biomedical optics, Tumors, Absorbance, Cell death, Absorption, Quantum efficiency

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Proceedings Article | 7 September 2018 Paper

Manipulation of photothermally generated microbubbles

R. Ramos-García, J. Ortega-Mendoza , J. Sarabia-Alonso, P. Zaca-Morán, A. Padilla-Vivanco, C. Toxqui-Quitl, I. Rivas-Cambero, J. Ramírez Ramírez, S. A. Torres Hurtado

Proceedings Volume 10723, 107232R (2018) https://doi.org/10.1117/12.2321713

KEYWORDS: Optical fibers, Silver, Nanoparticles, Continuous wave operation, Absorption, Liquids, Light

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Proceedings Article | 7 September 2018 Paper

Assembly and 2D manipulation of colloidal crystal by temperature gradient

J. Ramírez Ramírez, J. Vazquez Lozano, U. Ruiz Corona, R. Ramos-García

Proceedings Volume 10723, 107232O (2018) https://doi.org/10.1117/12.2321221

KEYWORDS: Crystals, Particles, Photonic crystals, Titanium, Laser crystals, Crystallography, Optical tweezers, Silica, Absorption, Thin films

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Proceedings Article | 18 August 2018 Paper

Speckle contrast calculation based on pixels correlation: spatial analysis

B. Coyotl-Ocelotl, J. Juarez Ramirez, R. Ramos-Garcia, R. Chiu, Teresita Spezzia-Mazzocco, J. Ramirez-San-Juan

Proceedings Volume 10749, 1074903 (2018) https://doi.org/10.1117/12.2321271

KEYWORDS: Speckle, Laser speckle contrast imaging, Spatial analysis, Numerical analysis, Speckle pattern, Image analysis, Blood circulation, Sensors, Image processing, Data modeling

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Proceedings Article | 18 August 2018 Paper

Contrast temporal analysis using correlation between frames

J. C. Juarez Ramirez, B. Coyotl-Ocelotl, R. Ramos-Garcia, R. Chiu, Teresita Spezzia-Mazzocco, J. Ramirez-San-Juan

Proceedings Volume 10749, 1074904 (2018) https://doi.org/10.1117/12.2321286

KEYWORDS: Speckle, Speckle pattern, Mathematical modeling, Numerical analysis, Laser speckle contrast imaging, Blood circulation, Synthetic aperture radar, Visualization, Image processing, Diamond

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Proceedings Article | 12 February 2018 Presentation + Paper

Efficient in vitro photodynamic inactivation of Candida albicans by repetitive light doses

S. A. Torres-Hurtado, J. Ramírez Ramírez, R. Ramos-García, J. C. Ramírez-San-Juan, T. Spezzia-Mazzocco

Proceedings Volume 10476, 1047608 (2018) https://doi.org/10.1117/12.2289300

KEYWORDS: Picosecond phenomena, In vitro testing, Control systems, Yeast, Light, Resistance, Toxicity, Light sources, Light emitting diodes, Diodes

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SPIE Journal Paper | 13 October 2017 Open Access

Toward jet injection by continuous-wave laser cavitation

Carla Berrospe Rodríguez, Claas Willem Visser, Stefan Schlautmann, David Fernandez Rivas, Rubén Ramos-García

JBO, Vol. 22, Issue 10, 105003, (October 2017) https://doi.org/10.1117/12.10.1117/1.JBO.22.10.105003

KEYWORDS: Liquids, Continuous wave operation, Cavitation, Skin, Pulsed laser operation, Microfluidics, Interfaces, Medicine, Laser systems engineering, Nd:YAG lasers

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SPIE Journal Paper | 12 June 2017 Open Access

Use of kurtosis for locating deep blood vessels in raw speckle imaging using a homogeneity representation

Hayde Peregrina-Barreto, Elizabeth Perez-Corona, Jose Rangel-Magdaleno, Ruben Ramos-Garcia, Roger Chiu, Julio Ramirez-San-Juan

JBO, Vol. 22, Issue 06, 066004, (June 2017) https://doi.org/10.1117/12.10.1117/1.JBO.22.6.066004

KEYWORDS: Blood vessels, Speckle imaging, Speckle, Biological research, Blood circulation, Visual analytics, Visualization, Tissues, Laser speckle imaging, Tissue optics

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Proceedings Article | 16 September 2016 Paper

Convection currents enhancement of the spring constant in optical tweezers

J. Zenteno-Hernández, A. Gómez-Vieyra, S. A. Torres-Hurtado, J. Ramirez-San-Juan, R. Ramos-García

Proceedings Volume 9922, 99222J (2016) https://doi.org/10.1117/12.2236243

KEYWORDS: Particles, Convection, Optical tweezers, Absorption, Amorphous silicon, Thin films, Liquids, Glasses, Numerical simulations, Atmospheric particles

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Proceedings Article | 16 September 2016 Presentation + Paper

Generation of optimal annular vortex beams for orbital angular momentum transfer to microparticles

U. Ruiz, Rafael Paez, V. Arrizon, R. Ramos

Proceedings Volume 9922, 99220N (2016) https://doi.org/10.1117/12.2239046

KEYWORDS: Spiral phase plates, Optical components, Axicons, Spatial light modulators, Gaussian beams, Optical vortices, Particles, Optical tweezers, Bessel beams, Transmittance

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Proceedings Article | 14 March 2016 Paper

Size scaling with light patterned dielectrophoresis in an optoelectronic tweezers device

Angel Fuentes, Juan Carlos Rodriguez Luna, Joan Juvert, Ruben Ramos-Garcia, Steven Neale

Proceedings Volume 9759, 97590P (2016) https://doi.org/10.1117/12.2209624

KEYWORDS: Particles, Dielectrophoresis, Optoelectronics, Optoelectronic devices, Finite element methods, Projection systems, Digital micromirror devices, Microelectromechanical systems, Lithography, Manufacturing, Liquids, Microscopes, Amorphous silicon, Photoresistors, Dielectric filters

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Proceedings Article | 24 August 2015 Paper

Visualization of deep blood vessels in speckle imaging using homogeneity measurement of the co-occurrence matrix

Jose Arias-Cruz, Cruz Perez-Corona, Hayde Peregrina-Barreto, Ruben Ramos-Garcia, Julio Cesar Ramirez-San-Juan

Proceedings Volume 9660, 96601O (2015) https://doi.org/10.1117/12.2196206

KEYWORDS: Blood vessels, Visualization, Speckle, Scattering, Image processing, Image analysis, Speckle imaging, Laser scattering, Skin, In vitro testing

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Proceedings Article | 24 August 2015 Paper

Implementation of focusing and redirecting light through highly scattering media

B. Coyotl-Ocelotl, R. Porras-Aguilar, R. Ramos-Garcia, J. C. Ramirez-San-Juan

Proceedings Volume 9660, 96601X (2015) https://doi.org/10.1117/12.2202820

KEYWORDS: Spatial light modulators, Scattering media, Light scattering, Wavefronts, Sensors, Detection and tracking algorithms, Cameras, Image segmentation, Light wave propagation, Tissue optics

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Proceedings Article | 16 September 2014 Paper

Holographic generation of vector beams with upper-bound diffraction efficiency

Rafael Páez López, Guadalupe Méndez, Maximino Arroyo-Carrasco, Ruben Ramos-García

Proceedings Volume 9164, 91642V (2014) https://doi.org/10.1117/12.2061157

KEYWORDS: Computer generated holography, Holograms, Polarization, Bessel beams, Spatial light modulators, Holography, Interferometers, Polarizers, Diffraction, Optical tweezers

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Proceedings Article | 16 September 2014 Paper

Trapping and manipulation of microparticles using Rayleigh convection generated by laser-induced heating of an absorbing thin film

S. Torres-Hurtado, E. Flores-Flores, G. Beltran-Perez, Steven Neale, J. Ramirez-San-Juan, R. Ramos-García

Proceedings Volume 9164, 91643C (2014) https://doi.org/10.1117/12.2061266

KEYWORDS: Particles, Convection, Thin films, Optical tweezers, Amorphous silicon, Numerical simulations, Spatial resolution, Absorption, Microscopes, Glasses

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Proceedings Article | 18 November 2013 Paper

Optical fiber trap: radiation pressure effect on inorganic and organic micro-particles

H. Cerecedo-Núñez, J. Alvarado-Zacarías, P. Padilla-Sosa, M. Basurto-Pensado, M. May-Alarcón, R. Ramos-García, L. Beltrán-Parrazal

Proceedings Volume 8785, 878566 (2013) https://doi.org/10.1117/12.2026435

KEYWORDS: Optical fibers, Particles, Radiation effects, Structured optical fibers, Optical tweezers, Bacteria, Microscopes, Geometrical optics, Optical spheres, Refractive index

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Proceedings Article | 15 March 2013 Paper

Liquid jet generated by thermocavitation bubbles within a droplet

J. Padilla-Martinez, Darren Banks, J. Ramirez-San-Juan, G. Aguilar, R. Ramos-Garcia

Proceedings Volume 8611, 86111J (2013) https://doi.org/10.1117/12.2004686

KEYWORDS: Liquids, Cavitation, Continuous wave operation, Glasses, Acoustics, Wave propagation, Microscopes, Video, Copper, Interfaces

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Proceedings Article | 11 October 2012 Paper

Optodielectrophoretic hologram recording in hybrid liquid crystals devices

A. Fuentes Garcia, M. Granados Luyando, M. Vazquez Nicolas, Pere Roca i Cabarrocas, J. Ramirez-San-Juan, R. Ramos Garcia

Proceedings Volume 8475, 84750X (2012) https://doi.org/10.1117/12.930756

KEYWORDS: Liquid crystals, Holograms, Electrodes, Diffraction, Amorphous silicon, Crystals, Helium neon lasers, Absorption, LCDs, Dielectrophoresis

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Proceedings Article | 10 October 2012 Paper

Optical trapping with photorefractive electric fields

S. A. Torres-Hurtado, B. M. Villegas-Vargas, N. Korneev, J. C. Ramirez-San-Juan, R. Ramos-Garcia

Proceedings Volume 8458, 845825 (2012) https://doi.org/10.1117/12.930741

KEYWORDS: Particles, Crystals, Photovoltaics, Optical tweezers, Dielectrics, Holography, Microscopes, Plasmons, Interfaces, Laser crystals

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Proceedings Article | 26 October 2011 Paper

Thermocavitation as a tool for stratum corneum permeation

J. P. Padilla-Martínez, J. Ramírez-San-Juan, R. Ramos-García, F. Sun, G. Aguilar

Proceedings Volume 8011, 80112Z (2011) https://doi.org/10.1117/12.901583

KEYWORDS: Cavitation, Tissues, Breast, Microscopes, Continuous wave operation, Liquids, Video, Solids, Pulsed laser operation, Copper

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Proceedings Article | 9 September 2011 Paper

Rectified Brownian motion by using optical ratchets

Javier Silva-Barranco, Ulises Ruiz-Corona, V. Arrizon, M. Arias-Estrada, Ruben Ramos-García

Proceedings Volume 8097, 80971W (2011) https://doi.org/10.1117/12.894450

KEYWORDS: Particles, Latex, Thermography, Teeth, Modulation, Spatial light modulators, Modulators, Phase contrast, Microscopes, Control systems

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Proceedings Article | 9 September 2011 Paper

Temporal evolution of thermocavitation bubbles using high speed video camera

J. Padilla-Martinez, G. Aguilar, J. Ramirez-San-Juan, R. Ramos-García

Proceedings Volume 8097, 809727 (2011) https://doi.org/10.1117/12.894467

KEYWORDS: Cavitation, Video, Cameras, Continuous wave operation, Absorption, High speed cameras, Explosives, Solids, Copper, Microscopes

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Proceedings Article | 9 September 2011 Paper

Optically induced Zn/ZnO nanoparticles selective deposition on single-mode fiber optic end

J. Ortega-Mendoza, F. Chávez, P. Zaca-Moran, R. Ramos-Garcia, C. Felipe, G. Pérez-Sánzhez, Jaime Gutiérrez, O. Goiz

Proceedings Volume 8097, 80971X (2011) https://doi.org/10.1117/12.892921

KEYWORDS: Particles, Nanoparticles, Zinc oxide, Zinc, Optical fibers, Single mode fibers, Beam propagation method, Gaussian beams, Fiber optics, Laser scattering

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Proceedings Article | 28 August 2010 Paper

Thermocavitation and its application for fabrication of micron-sized holes on metallic and dielectric thin films

J. Ramirez-San-Juan, J. Padilla-Martinez, P. Zaca Moran, E. Aboytes-Rodriguez, A. Martinez-Cantón, R. Ramos-Garcia

Proceedings Volume 7762, 77621E (2010) https://doi.org/10.1117/12.861314

KEYWORDS: Cavitation, Thin films, Titanium, Dielectrics, Continuous wave operation, Pulsed laser operation, Laser ablation, Glasses, Light sources, Solids

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Proceedings Article | 23 February 2010 Paper

Cavitation induced by CW lasers in absorbing liquids

J. Ramirez-San-Juan, E. Rodriguez-Aboytes, A. Martínez-Canton, O. Baldovino-Pantaleon, S. Torres-Hurtado, A. Robledo-Martinez, N. Korneev, R. Ramos-Garcia

Proceedings Volume 7562, 756211 (2010) https://doi.org/10.1117/12.842370

KEYWORDS: Cavitation, Liquids, Continuous wave operation, Infrared lasers, Absorption, Infrared radiation, Streak cameras, Ultrasonics, Tissues, Pulsed laser operation

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Proceedings Article | 29 August 2008 Paper

Sorting of microparticles by optical landscapes generated with a spatial light modulator

Ulises Ruiz-Corona, Victor Arrizon, Julio Ramirez-San-Juan, Ruben Ramos-Garcia

Proceedings Volume 7038, 703827 (2008) https://doi.org/10.1117/12.797197

KEYWORDS: Particles, Diffractive optical elements, Spatial light modulators, Optical tweezers, Fourier transforms, Diffraction, Diffraction gratings, Computer generated holography, Holograms, Optical design

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Proceedings Article | 27 August 2008 Paper

Polarization-dependent nonlinear phase contrast by using dye-doped nematic liquid crystals

Rosario Porras-Aguilar, Marcelo Iturbe-Castillo, Julio Ramirez-San-Juan, Oscar Baldovino-Pantaleon, David Sanchez de la Llave, Ruben Ramos-Garcia, Luis Arroyo-Carrasco

Proceedings Volume 7050, 705006 (2008) https://doi.org/10.1117/12.791556

KEYWORDS: Phase contrast, Polarization, Nonlinear filtering, Liquid crystals, Optical filters, Nonlinear optics, Tunable filters, Visualization, Phase shift keying, Microscopes

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Proceedings Article | 5 September 2007 Paper

Flow-assisted collection of DNA molecules on silica beads

N. Korneev, R. Ramos-García, J. C. Ramirez-San-Juan, E. Rodriguez-Aboytes, M. Cárdenas-García

Proceedings Volume 6644, 664427 (2007) https://doi.org/10.1117/12.731802

KEYWORDS: Absorption, Molecules, Silica, Optical tweezers, Glasses, Luminescence, Liquids, Molecular lasers, Bacteria, Particles

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Proceedings Article | 5 September 2007 Paper

Cavitation induced by continuous wave lasers

J. C. Ramirez-San-Juan, E. Rodriguez-Aboytes, N. Korneev, O. Baldovinos-Pantaleon, R. Chiu-Zarate, G. Gutiérrez-Juárez, R. Dominguez-Cruz, R. Ramos-García

Proceedings Volume 6644, 66441M (2007) https://doi.org/10.1117/12.734894

KEYWORDS: Cavitation, Continuous wave operation, Absorption, Copper, Phase contrast, Pulsed laser operation, Light scattering, Nd:YAG lasers, Microscopes, Absorbance

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Proceedings Article | 16 May 2007 Paper

High Kerr optical nonlinearity observed in a liquid crystal by Z-scan technique

R. Domínguez-Cruz, A. Padilla-Mijares, A. Méndez-Pérez, G. Romero-Galván, M. Panduro-Mendoza, R. Ramos-García

Proceedings Volume 6422, 64221O (2007) https://doi.org/10.1117/12.742373

KEYWORDS: Liquid crystals, Nonlinear optics, Refractive index, Transmittance, Molecules, Absorption, Refraction, Helium neon lasers, Continuous wave operation, Liquids

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Proceedings Article | 15 September 2006 Paper

Nonlinear phase contrast microscope

L. Olivos-Pérez, M. Iturbe-Castillo, M. Sánchez-de-la-Llave, R. Ramos-García, C. Treviño-Palacios

Proceedings Volume 6332, 633210 (2006) https://doi.org/10.1117/12.679682

KEYWORDS: Microscopes, Polarization, Phase contrast, Nonlinear filtering, Liquid crystals, Refractive index, Nonlinear optics, Optical filters, Light sources, Optical microscopes

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Proceedings Article | 15 September 2006 Paper

Simultaneous exhibition of positive and negative nonlinear refractive index in dye-doped liquid crystal in a Z-scan experiment

M. Iturbe-Castillo, R. Ramos-García, A. Rodriguez-Rosales

Proceedings Volume 6332, 63320U (2006) https://doi.org/10.1117/12.681309

KEYWORDS: Polarization, Liquid crystals, Transmittance, Refractive index, Polarizers, Absorption, Thermal effects, Photodetectors, Nonlinear response

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Proceedings Article | 11 September 2006 Paper

Characterization of an interferometric optical sieve for particle sorting

K. Volke-Sepulveda, R. Ramos-García, I. Ricardez-Vargas

Proceedings Volume 6326, 632616 (2006) https://doi.org/10.1117/12.679857

KEYWORDS: Particles, Refractive index, Optical spheres, Latex, Modulation, Solids, Interferometry, Optical tweezers, Microfluidics, Optical sorting

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Proceedings Article | 27 February 2006 Paper

Epoxy resin holograms

B. Ruiz-Limón, G. B. J. Wetzel, A. Olivares-Pérez, E. L. Ponce-Lee, R. Ramos-Garcia, S. Toxqui López, M. P. Hernández-Garay, I. Fuentes-Tapia

Proceedings Volume 6136, 613614 (2006) https://doi.org/10.1117/12.647143

KEYWORDS: Holograms, Epoxies, Diffraction, Refractive index, Holography, Holographic interferometry, Digital holography, Diffraction gratings, Computer simulations, Modulation

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Proceedings Article | 10 February 2006 Paper

Chromatic contrast in microscopes by a photoluminescent material

E. Ponce-Lee, A. Olivares-Pérez, R. Ramos-García, B. Ruiz-Limón, S. Toxqui-López, M. Hernández-Garay, I. Fuentes-Tapia

Proceedings Volume 6046, 604613 (2006) https://doi.org/10.1117/12.674479

KEYWORDS: Luminescence, Microscopes, Absorbance, Colorimetry, Ultraviolet radiation, Glucose, Nondestructive evaluation, Chemical species, Eye, Photomicroscopy

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Proceedings Article | 30 August 2005 Paper

Colossal optical nonlinear effects in the nematic-isotropic temperature transition in azo dye-doped liquid crystals

I. Lazo-Martinez, I. Guizar-Iturbide, A. Olivares-Perez, C. Trevino-Palacios, R. Ramos-Garcia

Proceedings Volume 5936, 59360Y (2005) https://doi.org/10.1117/12.615504

KEYWORDS: Liquid crystals, Diffraction, Glasses, Nonlinear optics, Diffraction gratings, Refractive index, Doping, Absorption, Light scattering, Temperature metrology

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Proceedings Article | 18 August 2005 Paper

Different intensity distribution obtained with an axicon

Marcelino Anguiano-Morales, M. Mendez-Otero, Sabino Chavez-Cerda, M. Iturbe-Castillo, Ruben Ramos-Garcia

Proceedings Volume 5876, 587617 (2005) https://doi.org/10.1117/12.618003

KEYWORDS: Axicons, Bessel beams, Opacity, Modulation, CCD cameras, Refractive index, Wavefronts, Silver, Wave propagation, Crystals

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Proceedings Article | 21 October 2004 Paper

Raman spectroscopy applied to molecular transformation of photochromic polymers

R. Delgado Macuil, V. Lopez Gayou, M. Rojas Lopez, A. Orduna-Diaz, Ruben Ramos-Garcia

Proceedings Volume 5622, (2004) https://doi.org/10.1117/12.590961

KEYWORDS: Luminescence, Raman spectroscopy, Polymers, Absorption, Ultraviolet radiation, Fluorescence spectroscopy, Argon ion lasers, Molecular spectroscopy, Fabrication, Photochromic materials

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Proceedings Article | 18 October 2004 Paper

Normal-light streak effect in optically trapped hollow microspheres

Ibis Ricardez-Vargas, David Iturbe-Castillo, Ruben Ramos-Garcia, Karen Volke-Sepulveda, Victor Ruiz-Cortes

Proceedings Volume 5514, (2004) https://doi.org/10.1117/12.556997

KEYWORDS: Optical spheres, Particles, Optical tweezers, Interfaces, Gaussian beams, Glasses, Scattering, Refractive index, Argon ion lasers, Optical micromanipulation

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Proceedings Article | 17 February 2003 Paper

All-optical switching by total internal reflection in nonlinear interface of (2+1)D beams in SBN61:Ce

Edgar Alvarado-Mendez, Miguel Torres-Cisneros, Oscar Ibarra-Manzano, Jose Andrade-Lucio, R. Rojas-Laguna, C. Garcia-Teran, J. Estudillo-Ayala, B. Gonzalez-Rolon, J. Alvarez-Jaime, H. Gamboa-Rosales, H. Zavala-Fernandez, Ruben Ramos-Garcia

Proceedings Volume 4833, (2003) https://doi.org/10.1117/12.474896

KEYWORDS: Interfaces, Crystals, Laser crystals, Switching, Reflection, Dielectrics, Gaussian beams, Nonlinear crystals, Modulation, Light scattering

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Proceedings Article | 14 February 2003 Paper

Slow nonlinearities in bleached photographic film

David Sanchez-de-la-Llave, Marcelo Iturbe Castillo, Ruben Ramos Garcia

Proceedings Volume 4797, (2003) https://doi.org/10.1117/12.457765

KEYWORDS: Photography, Silver, Refractive index, Argon ion lasers, Transmittance, Absorption, Continuous wave operation, Nonlinear optics, Nonlinear filtering, Laser development

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Proceedings Article | 27 November 2002 Paper

Nonlinear phase contrast using a bacteriorhodopsin film

Marcelo Iturbe Castillo, J. Sanchez-de-la-Llave, Ruben Ramos Garcia, Eduardo Tepichin-Rodriguez, L. I. Olivos-Perez

Proceedings Volume 4789, (2002) https://doi.org/10.1117/12.456519

KEYWORDS: Phase contrast, Optical filters, Nonlinear filtering, Spherical lenses, Visibility, Fourier transforms, Optical alignment, Image analysis, Refractive index, Prisms

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Proceedings Article | 5 November 2002 Paper

Photo-EMF effect in polydiacetylene PTS

Ruben Ramos-Garcia, V. Camacho-Pernas, Carlos Trevino-Palacios, George Stegeman

Proceedings Volume 4802, (2002) https://doi.org/10.1117/12.452441

KEYWORDS: Crystals, Polymers, Excitons, Personal digital assistants, Absorption, Modulation, Polymerization, Modulators, Phase shift keying, Resistors

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Proceedings Article | 16 January 2002 Paper

Investigation of reflectance gratings in PVK-based photorefractive polymers by photo-EMF and self-diffraction techniques

Serguei Stepanov, Ruben Ramos-Garcia, V. Camacho-Pernas, Svetlana Mansurova, Reinhard Bittner, Klaus Meerholz

Proceedings Volume 4462, (2002) https://doi.org/10.1117/12.452731

KEYWORDS: Polymers, Diffusion, Modulation, Photorefractive polymers, Crystals, Polymer thin films, Phase shift keying, Chromophores, Reflectivity, Signal detection

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SPIE Journal Paper | 1 November 2001

Real-time self-induced nonlinear optical Zernike-type filter in a bacteriorhodopsin film

Marcelo Iturbe Castillo, David Sanchez-de-la-Llave, Ruben Ramos-Garcia, L.I. Olivos-Perez, Luis Gonzalez, M. Rodriguez-Ortiz

OE, Vol. 40, Issue 11, (November 2001) https://doi.org/10.1117/12.10.1117/1.1412425

KEYWORDS: Optical filters, Nonlinear filtering, Fourier transforms, Refractive index, Nonlinear optics, Light sources, Optical alignment, Imaging systems, Phase contrast, Optical properties

Proceedings Article | 30 March 2001 Paper

Optical active pupil based on PDLC

Mario Perez-Cortes, Arturo Olivares-Perez, Ruben Ramos-Garcia, V. Sanchez-Villicana, Mauricio Ortiz-Gutierrez

Proceedings Volume 4294, (2001) https://doi.org/10.1117/12.420782

KEYWORDS: Active optics, Polymers, Liquid crystals, Glasses, Electro optics, Diffusers, Electronic components, Iris, Optical switching, LCDs

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Proceedings Article | 19 July 1999 Paper

One-dimensional bright spatial soliton internal reflection in a PRC-linear interface

Edgar Alvarado-Mendez, Miguel Torres-Cisneros, Jose Andrade-Lucio, J. Avina-Cervantes, Ruben Ramos-Garcia, Marcelo Iturbe Castillo, Victor Vysloukh, Jose Javier Sanchez-Mondragon

Proceedings Volume 3749, (1999) https://doi.org/10.1117/12.354990

KEYWORDS: Spatial solitons, Interfaces, Diffusion, Solitons, Crystals, Laser crystals, Nonlinear optics, Diffraction, Refractive index, Transient nonlinear optics

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Showing 5 of 67 publications

Conference Committee Involvement (18)

Optical Trapping and Optical Micromanipulation XXII

3 August 2025 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XXI

18 August 2024 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XX

20 August 2023 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XIX

21 August 2022 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XVIII

2 August 2021 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XVII

24 August 2020 | Online Only, California, United States

Optical Trapping and Optical Micromanipulation XVI

11 August 2019 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XV

19 August 2018 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XIV

6 August 2017 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XIII

28 August 2016 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation XII

9 August 2015 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation IX

12 August 2012 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation VIII

21 August 2011 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation VII

1 August 2010 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation VI

2 August 2009 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation V

10 August 2008 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation IV

26 August 2007 | San Diego, California, United States

Optical Trapping and Optical Micromanipulation III

13 August 2006 | San Diego, California, United States

Showing 5 of 18 Conference Committees

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