A5030430194- Laser Material Processing Techniques
- Laser-induced spectroscopy and plasma
- Nonlinear Optical Materials Studies
- Phase-change materials and chalcogenides
- Advanced Fluorescence Microscopy Techniques
- Ocular and Laser Science Research
- Glass properties and applications
- Laser-Ablation Synthesis of Nanoparticles
- Advanced Surface Polishing Techniques
- Adhesion, Friction, and Surface Interactions
- Laser-Matter Interactions and Applications
- Photoacoustic and Ultrasonic Imaging
- Silicon Nanostructures and Photoluminescence
- Advanced Fiber Laser Technologies
- Surface Roughness and Optical Measurements
- Thin-Film Transistor Technologies
- Photonic Crystals and Applications
- Optical Coherence Tomography Applications
- Near-Field Optical Microscopy
- Chalcogenide Semiconductor Thin Films
- Diamond and Carbon-based Materials Research
- Optical Imaging and Spectroscopy Techniques
- Solid State Laser Technologies
- Photonic and Optical Devices
- Thermography and Photoacoustic Techniques
Instituto de Óptica "Daza de Valdés"
2015-2024
Consejo Superior de Investigaciones Científicas
2010-2024
National Technical Information Service
2024
Argonne National Laboratory
2024
University of Chicago
2024
Office of Scientific and Technical Information
2024
Technical University of Munich
2021
Brno University of Technology
2019
Optica
2018-2019
Laboratoire Hubert Curien
2016
Structural switch for fast switching Phase-change materials are important computer memory. They can quickly from glassy to crystalline using a thermal pulse and then lock in that structure long time at lower temperature. Zalden et al. probed the underlying atomic of two phase-change during this ultrafast x-rays simulations (see Perspective by Rao ). A liquid-liquid phase transition both allowed high temperatures. The lower-temperature glass locks structure, allowing long-term memory storage....
An emerging theme in cell biology is that surface receptors need to be considered as part of supramolecular complexes proteins and lipids facilitating specific receptor conformations distinct distributions, e.g., at the immunological synapse. Thus, a new goal develop bioimaging not only locates live cells but can also probe their environment. Such technique demonstrated here using fluorescence lifetime imaging green fluorescent protein (GFP). We first show, by time-correlated single-photon...
The phase transformation dynamics induced in Ge2Sb2Te5 films by picosecond laser pulses were studied using real-time reflectivity measurements with subnanosecond resolution. Evidence was found that the thermal diffusivity of substrate plays a crucial role determining ability to crystallize and amorphize. A film/substrate configuration optimized heat flow conditions for ultrafast cycling designed produced. In this system, we achieved reversible transformations large optical contrast...
Laser-induced periodic surface structures (LIPSS) are a universal phenomenon observed in all classes of solid materials, giving rise to variety self-assembled subwavelength with different symmetries. These promising features have opened new opportunities for laser structuring materials wide range applications, including plasmonics, nanophotonics, nanoelectronics, sensing, and even mechanics. However, there is an ongoing debate about the formation mechanism LIPSS, current picture stems mainly...
The wettability of a material surface is an essential property that can define the range applications it be used for. In particular case steel, industrial are countless but sometimes limited because lack control over its properties. Although different strategies have been proposed to tune wetting behavior metal surfaces, most them require use processes such as coatings with materials or plasma/chemical etching. this work, we present two laser-based direct-write allow tuning properties 1.7131...
The formation of self-organized laser-induced periodic surface structures (LIPSS) in metals, semiconductors, and dielectrics upon pulsed laser irradiation is a well-known phenomenon, receiving increased attention because their huge technological potential. For the case major role this process played by plasmon polaritons (SPPs) propagating at interface metal with medium incidence. Yet, simple advanced models based on SPP propagation sometimes fail to explain experimental results, even basic...
A whole‐field time‐domain fluorescence lifetime imaging (FLIM) microscope with the capability to perform optical sectioning is described. The excitation source a mode‐locked Ti:Sapphire laser that regeneratively amplified and frequency doubled 415 nm. Time‐gated intensity images at increasing delays after are acquired using gated microchannel plate image intensifier combined an intensified CCD camera. By fitting single or multiple exponential decay each pixel in field of view time‐gated...
Abstract Fluorescence lifetime imaging (FLIM) depends on the fluorescence decay differences between tissues to generate image contrast. In present study FLIM has been applied fixed (but unstained) breast cancer demonstrate feasibility of this approach for histopathological assessment. As method relies natural autofluorescence, it may be possible circumvent tissue processing altogether and so potential a powerful new in vivo via an endoscopic or per‐operative variety organs, as well research...
Time resolved imaging has been used to analyze structural transformations induced by intense 100 fs laser pulses in amorphous GeSb films. Above a threshold of 19 mJ/ ${\mathrm{cm}}^{2}$ the data show formation transient nonequilibrium state excited material within 300 fs. The results are consistent with an electronically induced, amorphous-to-crystalline phase transition.
We have developed a wide-field time-resolved imaging system to image quantitatively both the fluorescence lifetime and rotational correlation time of fluorophore. Using polarization-resolved imager, we simultaneously orthogonal polarization components emission onto time-gated intensified CCD. demonstrate solvent viscosity variations through fluorescein in multiwell plate apply this technique probe microviscosity live cells.
We have studied plasma formation and relaxation dynamics along with the corresponding topography modifications in fused silica sapphire induced by single femtosecond laser pulses (800 nm 120 fs). These materials, representative of high bandgap amorphous crystalline dielectrics, respectively, require nonlinear mechanisms to absorb light. The study employed a time-resolved microscopy technique that allows obtaining reflectivity transmission images material surface at well-defined temporal...
Phase transformations of crystalline Ge2Sb2Te5 films upon pulsed laser irradiation have been studied using in situ reflectivity measurements with temporal resolution. Two different configurations allowed point probing nanosecond resolution and imaging subpicosecond micrometer spatial The role the pulse duration fluence on dynamics phase change degree amorphization is discussed. Several advantageous features femtosecond compared to laser-induced are identified. Moreover, a high-resolution...
We report on the fabrication of laser-induced periodic surface structures in Cr films upon high repetition rate fs laser irradiation (up to 1 MHz, 500 fs, 1030 nm), employing beam scanning. Highly regular large-area (9 cm2) gratings with a relative diffraction efficiency 42% can be produced within less than 6 min. The ripple period at moderate and fluences is 0.9 μm, small 0.5 μm appearing lower energies. role parameters characteristics (LIPSS) studied discussed frame models presently used....
In this Letter, we report on the successful fabrication of low loss, high refractive index contrast waveguides via ion migration upon femtosecond laser writing in phosphate glass. Waveguides were produced two different glass compositions with and La(2)O(3) content. La-rich glass, a large increase guiding region was observed due to incoming La accompanied by out-diffusion K. The much smaller change La-less is caused rearrangements structure. These results confirm feasibility adapting...
Controlling plasmonic systems with nanometer resolution in transparent films and their colors over large nonplanar areas is a key issue for spreading use various industrial fields. Using light to direct self-organization mechanisms provides high-speed flexible processes meet this challenge. Here, we describe route the laser-induced of metallic nanostructures 3D. Going beyond production planar nanopatterns, demonstrate that ultrafast excitation combined nonlinear feedback nanocomposite thin...
We have applied fluorescence lifetime imaging (FLIM) to the autofluorescence of different kinds biological tissue in vitro, including animal sections and knee joints as well human teeth, obtaining two-dimensional maps with functional contrast. find that decay profiles are described by stretched exponential function (StrEF), which can represent complex nature tissue. The StrEF yields a continuous distribution lifetimes, be extracted an inverse Laplace transformation, additional information is...
Femtosecond time-resolved microscopy has been used to analyze the structural transformation dynamics (melting, ablation, and solidification phenomena) induced by intense $130\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$ laser pulses in single-crystalline (100)-germanium wafers on a time scale from $\ensuremath{\sim}100\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$ up $10\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$. Complementary information longer scales...
Self-assembly (SA) of molecular units to form regular, periodic extended structures is a powerful bottom-up technique for nanopatterning, inspired by nature. SA can be triggered in all classes solid materials, instance, femtosecond laser pulses leading the formation laser-induced surface (LIPSS) with period slightly shorter than wavelength. This approach, though, typically involves considerable material ablation, which leads an unwanted increase roughness. We present new strategy fabricate...
Simultaneous time-and-space resolved reflectivity and interferometric measurements over a temporal span of 300 ps have been performed in fused silica sapphire samples excited with 800 nm, 120 fs laser pulses at energies slightly well above the ablation threshold. The experimental results simulated frame multiple-rate equation model including light propagation. comparison evolution 400 nm clearly shows that two techniques interrogate different material volumes during course process. While...