Raúl Josué Hernández Hernández

Raúl Josué Hernández Hernández
Universidad Autónoma de San Luis Potosí | UASLP · Instituto de Física

PhD. Physics - University of Calabria (Italy)

About

52
Publications
7,179
Reads
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468
Citations
Citations since 2017
9 Research Items
295 Citations
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2017201820192020202120222023010203040506070
2017201820192020202120222023010203040506070
Introduction
My areas of interest and experience are optics-photonics, properties&light's interaction with materials. Microfluidics, design fabrication of systems for handling and confinement of micro particles with light beams, programming and simulation of optical forces, optical and dynamical properties of new materials (liquid crystals, chiral materials, active matter, Janus particles. Spectral analysis. Quantum optics experiments SPDC. Spin Ice. http://scholar.google.es/citations?user=cEpauPIAAAAJ&hl
Additional affiliations
March 2020 - January 2022
University of Barcelona
Position
  • PostDoc Position
October 2017 - February 2020
Consejo Nacional de Ciencia y Tecnología
Position
  • Researcher
October 2017 - January 2020
Universidad Nacional Autónoma de México
Position
  • University teacher
Education
March 2010 - December 2012
Università della Calabria
Field of study
  • Physics
August 2006 - January 2011
August 2000 - August 2004
Universidad Veracruzana
Field of study
  • Physics

Publications

Publications (52)
Article
We investigate the dynamics of chiral microparticles in a dual-beam optical trap. The chiral particles have the structure of spherical chiral microresonators, with a reflectance deriving from the supramolecular helicoidal arrangement. Due to the strong asymmetric response of the particles to light with a specific helicity and wavelength, their trap...
Article
We demonstrate the emergence of circular collective motion in a system of spherical light-propelled Brownian particles. Light-propulsion occurs as consequence of the coupling between the chirality of polymeric particles — left (L)- or right (R)- type — and the circularly-polarized light that irradiate them. Irradiation with light having the same he...
Article
Full-text available
We investigate phase separation in a chiral fluid, made of spinning ferromagnetic colloids that interact both via hydrodynamic and dipolar forces and collectively organize into separated circulating clusters. We show that, at high spinning frequency, hydrodynamics dominate over attractive magnetic interactions and impede coarsening, forcing the par...
Article
We study the pair interactions between magnetically driven colloidal microrotors with an anisotropic shape. An external precessing magnetic field induces a torque to these particles spinning them at a fixed angular frequency. When pair of rotors approach each other, the anisotropic particles interact via dipolar forces and hydrodynamic interactions...
Article
Full-text available
Correction for ‘Collective motion of chiral Brownian particles controlled by a circularly-polarized laser beam’ by Raúl Josué Hernández et al. , Soft Matter , 2020, 16 , 7704–7714, DOI: 10.1039/C9SM02404B.
Poster
Full-text available
The spatial properties of photon pairs produced by the process of spontaneous parametric down-conversion (SPDC) with an apertured zeroth-order Bessel-Gauss beam, were studied in theory and experiment. We developed a method that modifies the structured pump beam with the rotation of a half-plane aperture, and allows the selection of either one, or a...
Article
We demonstrate, both experimentally and theoretically, a method that allows us to modify the spatial properties of photon pairs produced by the process of spontaneous parametric down-conversion (SPDC) with an apertured, zeroth-order Bessel-Gauss beam. Concentrating on the use of a half-plane aperture, we show that the phase-matching conditions for...
Article
Microdroplets systems have attracted great interest because of their wide range of applications, easiness in processing and handling, feasibility in developing miniaturized devices with high performances and large flexibility. In this study, a stable emulsion based on different dye-doped chiral liquid crystals droplets has been engineered in order...
Article
Full-text available
Microfluidics generated liquid crystal (LC) droplets are currently used as microresonators in optofluidics applications due to their small size, narrow droplets diameter distributions, high Q-factor and tunability properties. In this work we report a short review regarding lasing from cholesteric liquid crystals (CLCs) confined in spherical microdr...
Article
Full-text available
We study the rotational dynamics of solid chiral and birefringent microparticles induced by elliptically polarized laser light in optical tweezers. We find that both reflection of left circularly polarized light and residual linear retardance affect the particle dynamics. The degree of ellipticity of laser light needed to induce rotations is found....
Conference Paper
Liquid crystal microresonators are widely used in optics and photonics applications due to their small dimensions, very high Q-factor and their tunability properties. Microfluidics allows a precise generation of liquid crystal droplets characterized by narrow droplets diameter distributions. Droplets with different internal configurations, bipolar...
Article
This manuscript reviews the main results from the investigations performed on solid chiral micro-particles based on polymerized cholesteric droplets. The procedures of particles generation, the structural characterization, optomechanics and microphotonics investigations, are shown. The aim of this work is to give a picture of the innovation introdu...
Article
Full-text available
Linearly polarized (LP) and unpolarized (UP) light are racemic entities since they can be described as superposition of opposite circularly polarized (CP) components of equal amplitude. As a consequence they do not carry spin angular momentum. Chiral resolution of a racemate, i.e. separation of their chiral components, is usually performed via asym...
Conference Paper
Full-text available
We perform an experimental and theoretical investigation of the simultaneous optical trapping and rotation of chiral microparticles. The coupling of linear and angular momentum, mediated by the light spin and the particle chiral reflectance, allows for fine tuning of chirality-induced optical forces and torques. This offers novel tools for optomech...
Conference Paper
Full-text available
We perform an experimental and theoretical investigation of the simultaneous optical trapping and rotation of spherulite-like chiral microparticles. The coupling of linear and angular momentum, mediated by the light spin and the microparticles chiral reflectance, allows for fine tuning of chirality-induced optical forces and torques. This offers no...
Article
Full-text available
Chirality is one of the most prominent and intriguing aspects of nature, from spiral galaxies down to aminoacids. Despite the wide range of living and non-living, natural and artificial chiral systems at different scales, the origin of chirality-induced phenomena is often puzzling. Here we assess the onset of chiral optomechanics, exploiting the co...
Article
Full-text available
A variety of chiral microspheres, each one possessing distinctive configurations of the molecular director, are studied. The process to obtain the solid particles is illustrated and some of their optical features is discussed. The optical properties of these objects depend from the emulsion preparation standards. The self-organized structures have...
Article
Full-text available
Multifunctional colloidal micro and nano-particles with controlled architectures have very promising properties for applications in bio and nanotechnologies. Here we report on the unique dichotomous dynamical behaviour of chiral spherical microparticles, either fluid or solid, manipulated by polarized optical tweezers. The particles are created usi...
Article
Full-text available
We investigate the manipulation and trapping features of polarization holographic tweezers with liquid-crystal (LC) droplets in water. The force related to light's polarization pattern translates isotropic particles, while for birefringent particles exert forces and torques in opposite directions depending on the position of the particle. Experimen...
Article
The photopolymerization of cholesteric liquid crystal droplets leads to the generation of solid chiral microspheres. The methodological approach of Cipparrone et al. reported on page 5773 enables control of the internal helical geometry of solid particles using dopant species in the precursor liquid crystal emulsion. The solid particles exhibit fas...
Article
Full-text available
The effect of the Magnus force in optical micromanipulation has been observed. An ad hoc experiment has been designed based on a one-dimensional optical trap that carries angular momentum. The observed particle dynamics reveals the occurrence of this hydrodynamic force, which is neglected in the common approach. Its measured value is larger than th...
Article
Full-text available
We report an investigation of manipulation and trapping capabilities of polarization holographic tweezers. A polarization gradient connected with a modulation of the ellipticity shows an optical force related to the polarization of the light that can influence optically isotropic particles. While in the case of birefringent particles an unconventio...
Article
We present a novel method for the efficient generation of even, odd, and helical Mathieu-Gauss beams of arbitrary order and ellipticity by means of a phase-only spatial light modulator (SLM). Our method consists of displaying the phase of the desired beam in the SLM; the reconstructed field is obtained on-axis following a spatial filtering process...
Article
Full-text available
The experimental generation of vector Bessel beams of different orders with TE and TM polarizations is demonstrated in the optical frequencies domain and in free space by means of a Mach-Zehnder interferometer. For the zero order beams, these modes correspond to the well known azimuthal and radial polarization states, whereas higher order versions...
Article
We demonstrate the experimental generation at optical frequencies of the lowest- and first-order Bessel beams with TE and TM polarizations in free space by means of a Mach-Zehnder interferometer. The polarization and angular momentum properties of these waves are analyzed and discussed.

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