A5053179679- Photorefractive and Nonlinear Optics
- Solid State Laser Technologies
- Luminescence Properties of Advanced Materials
- Advanced Fiber Laser Technologies
- Photonic and Optical Devices
- Glass properties and applications
- Photonic Crystals and Applications
- Plasmonic and Surface Plasmon Research
- Ferroelectric and Piezoelectric Materials
- Acoustic Wave Resonator Technologies
- Multiferroics and related materials
- Gold and Silver Nanoparticles Synthesis and Applications
- Nonlinear Optical Materials Studies
- Advanced Fiber Optic Sensors
- Random lasers and scattering media
- Crystal Structures and Properties
- Liquid Crystal Research Advancements
- Magnetic and transport properties of perovskites and related materials
- High-pressure geophysics and materials
- Silicon Nanostructures and Photoluminescence
- Perovskite Materials and Applications
- Thermal Radiation and Cooling Technologies
- Quantum optics and atomic interactions
- Optical properties and cooling technologies in crystalline materials
- Geological and Geochemical Analysis
Universidad Autónoma de Madrid
2015-2024
Science Council
2024
Pennsylvania State University
2007-2019
Argonne National Laboratory
2009-2019
University of Bern
2019
University of Surrey
2019
Consejo Nacional de Investigaciones Científicas y Técnicas
2016
Instituto Tecnológico Metropolitano
2016
Universidad Complutense de Madrid
2010
University of Houston
2009
Using spectroscopic ellipsometry, the room temperature refractive index and absorption versus wavelength of ferroelectric antiferromagnet bismuth ferrite, BiFeO3, are reported. The material has a direct band gap at 442nm (2.81eV). optical second harmonic generation, nonlinear coefficients were determined to be d15∕d22=0.20±0.01, d31∕d22=0.35±0.02, d33∕d22=−11.4±0.20, ∣d22∣=298.4±6.1pm∕V fundamental 800nm.
A prominent band centered at ∼1000–1300cm−1 and associated with resonant enhancement of two-phonon Raman scattering is reported in multiferroic BiFeO3 thin films single crystals. strong anomaly this occurs the antiferromagnetic Neel temperature, TN∼375°C. This composed three peaks, assigned to 2A4, 2E8, 2E9 modes. While all peaks were found be sensitive phase transition, 2E8 mode, particular, nearly disappears TN on heating, indicating a spin-two-phonon coupling BiFeO3.
The main properties of the ${\mathrm{Nd}}^{3+}\ensuremath{\rightarrow}{\mathrm{Yb}}^{3+}$ ${(}^{4}{F}_{3/2},{}^{2}{\stackrel{\ensuremath{\rightarrow}}{{F}_{7/2}}}^{4}{I}_{9/2},{}^{2}{F}_{5/2})$ energy transfer in yttrium aluminum borate nonlinear laser crystal have been studied. This host has found especially suitable for efficient because good matching between phonon and ${}^{4}{F}_{3/2}({\mathrm{Nd}}^{3+}{)\ensuremath{-}}^{2}{F}_{7/2}({\mathrm{Yb}}^{3+})$ gap (\ensuremath{\cong}1000...
The interplay between spin waves (magnons) and electronic structure in materials leads to the creation of additional bands associated with energy levels which are called magnon sidebands. large difference scales magnons (meV) (eV) makes this direct interaction weak hence sidebands difficult probe. Linear light absorption scattering techniques at low temperatures traditionally used probe these Here we show that optical second-harmonic generation, as lowest-order nonlinear process, can...
Abstract The ability of Strontium Barium Niobate crystal as a two‐dimensional nonlinear optical multiple‐wavelength‐and‐direction converter is demonstrated, showing how harmonic generation can be obtained in an extremely large spectral range. whole visible region continuously generated without any angle or temperature tuning by using different schemes involving SHG and THG configurations. dominant frequency conversion mechanisms acting each case are experimentally determined. system act...
Using confocal Raman and fluorescence spectroscopic imaging in 3-dimensions, we show direct evidence for Nd 3+ -Nd interactions across grain boundaries (GBs) :YAG laser ceramics.It is clearly shown that segregation takes place at GBs leading to self-fluorescence quenching which affects a volume fraction as high 20%.In addition, clear trend of increasing spatial inhomogeneities concentration when the doping levels exceeds 3 at%, not detected by standard spectrometry techniques.These results...
It has been shown that the Earth’s inner core an axisymmetric anisotropic structure with seismic waves traveling ∼3% faster along polar paths than equatorial directions. Hemispherical patterns of solid are rather complex, and commonly used hexagonal-close-packed iron phase might be insufficient to account for seismological observations. We show data we collected in good agreement presence two anisotropically specular east west hemispheres. The detected travel-time anomalies can only...
The influence of the addition 1 mol% Tm 2 O 3 on nanocrystallization LaF in a glass composition 55 SiO –20 Al –15 Na –10 (mol%) has been studied. affects phase separation and delays onset crystallization with respect to undoped glass. Additionally, maximum crystal size is slightly greater than that glass–ceramics. microstructural compositional changes matrix have studied using several techniques, including viscosity, dilatometry, X‐ray neutron diffraction ( XRD , ND ), quantitative Rietveld...
Solid-state lasers constitute essential tools in a variety of scientific and technological areas, being available many different designs. However, although nanolasing has been successfully achieved for dyes semiconductor gain media associated with plasmonic structures, the operation solid-state beyond diffraction limit not reported yet. Here, we demonstrate room temperature laser action subwavelength confinement Nd(3+)-based by means localized surface plasmon resonances supported chains...
In this Letter we have used the optical pump induced thermal loading to drive Nd(3+) a doped Sr(0,47)Ba(0.53)(Nb)(3))(2) laser crystal during operation through its ferroelectric phase transition. We demonstrate that lasing is possible below, at, and above For temperatures close (approximately 105 degrees C) spatial distribution of radiation remarkably affected. This feature, which leads gain depression, can be explained in terms strong temperature dependence thermo-optic coefficient...
Amorphous silicon is deposited within optical fibers by a high pressure microfluidic deposition process and characterized via Raman spectroscopy. All-optical modulation of 1.55μm light guided through the core demonstrated using free carrier absorption generated 532nm pump pulse. Modulation depths up to 8.26dB frequencies 1.4MHz are demonstrated.
Spin-charge-lattice coupling mediated by multimagnon processes is demonstrated in multiferroic BiFeO3. Experimental evidence of two- and three-magnon excitations as well at electronic energy scales high temperatures are reported. Temperature dependent Raman experiments show up to five resonant enhancements the two-magnon excitation below Néel temperature. These shown be collective interactions between on-site Fe d-d resonance, phonons, multimagnons.
We report on the fabrication and microspectroscopy imaging of femtosecond laser written double-filament based Nd3+:MgO:LiNbO3 optical waveguides. The waveguiding high refractive-index regions are identified by blueshifts Nd3+ ion fluorescence lines with no deterioration in efficiency, whereas filamentary low-index both a line redshift efficiency reduction. lattice structural micromodifications at origin waveguide formation changes have been investigated means confocal micro-Raman...
Periodic arrays of silver nanoparticles on a Nd3+-doped periodically poled ferroelectric laser crystal are selectively self-assembled by photochemical methods. By exploiting the unique features plasmonic nanostructures to concentrate electromagnetic fields, an enhancement Nd3+ luminescence is demonstrated as well remarkable increase quadratic nonlinear second harmonic generation factor 20, which occurs with periodicity metallic arrays. As service our authors and readers, this journal...
Ferroelectric patterning is often used in advanced photonics and optoelectronic devices to increase their operational bandwidth functionality, providing novel unique performances. However, the extension of ferroelectric structures two‐dimensional geometries currently limited very few oxides phosphates systems, which constrains its current future applications. Here, careful processing based on e‐beam lithography poling employed fabricate first example a nonlinear photonic crystal Barium...
In this paper the temperature evolution of main Raman peak at about 630 cm−1 has been studied in order to detect ferroelectric paraelectric phase transition strontium barium niobate (SrxBa1−xNb2O6) crystals with different stoichiometries (x = 0.33, 0.5 and 0.61). Both its wavenumber width have shown be strongly dependent on display clear anomalies around Curie temperature. The obtained results manifest usefulness simple unpolarized spectra probe changes Tc as a result modifications crystal...
We report on highly controllable ferroelectric domain inversion in Yb3+ doped LiNbO3 laser crystal. The patterns are fabricated by direct electron beam writing without any previous masking process. Square lattices of inverted domains with diameters and distance between as low 1 μm demonstrated. lateral growth the is analyzed a function applied charge threshold values for 1–10 length scale determined. Spatially resolved temperature fluorescence spectroscopy non-collinear second harmonic...
Emergent phenomena driven by light–matter interaction may have potential applications in next-generation domain wall nanoelectronics utilizing polycrystalline ferroelectrics.
In this work a systematic optical characterization of the NdAl3(BO3)4 (NAB) crystal has been carried out by means spectroscopic measurements. The energy levels (118) Nd3+ constituent ions have identified and labeled appropriate field quantum numbers (μ=1/2 or μ=3/2). Laser site selective experiments revealed presence two nonequivalent environments for ions. From room temperature absorption emission spectra using Judd–Ofelt formalism cross sections efficiency (η=0.1) metastable state F3/24...
A two-dimensional periodic arrangement of alternating ferroelectric domains in LiNbO3, with asymmetric domain duty cycle has been used to demonstrate that counterpropagating beams along the polar axis can generate disparate second harmonic patterns, which are nonsymmetrical respect source and point observation. These findings provide alternative routes dissimilar light-matter interaction processes structures assembled onto surfaces, including metals for plasmonics or biological compounds.
Broadly tunable multiple high-harmonic conical beams have been generated by means of a multistep χ (2) cascade processes in two dimensional nonlinear photonic crystal.The structure consists square lattice inverted hexagonal domains with diameters and distances between as low 1 μm.The large number reciprocal vectors provided both the shaped domains, along imperfections on size shape individual make possible simultaneous generation second up to fifth harmonic single using different types phase...
Homogeneous linewidths below 10 kHz are reported for the first time in high-quality Eu3+ doped Y 2O3 transparent ceramics. This result is obtained on 7F0→5D0 transition ceramics and corresponds to an improvement of nearly one order magnitude compared previously values Furthermore, we observed spectral hole lifetimes ∼15 min that long enough enable efficient optical pumping nuclear hyperfine levels. Additionally, different concentrations (up 1.0%) were studied, resulting increase up a factor...