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Vortex Dynamics and Optical Vortices || Ultrashort Extreme Ultraviolet Vortices
摘要： Optical vortices are very attractive because they transport a well-defined orbital angular momentum (OAM) associated with the singularity of the beam. These singular beams, commonly generated in the optical regime, are used in a wide range of applications: communication, micromanipulation, microscopy, among others. The production of OAM beams in the extreme ultraviolet (XUV) and X-ray regimes is of great interest as it allows to extend the applications of optical vortices down to the nanometric scale. Several proposals have been explored in order to generate XUV vortices in synchrotrons and FEL facilities. Here, we study the generation of XUV vortices through high-order harmonic generation (HHG). HHG is a unique source of coherent radiation extending from the XUV to the soft X-ray regime, emitted in the form of attosecond pulses. When driving HHG by OAM beams, highly charged XUV vortices with unprecedented spatiotemporal properties are emitted in the form of helical attosecond beams. In this chapter, we revise our theoretical work in the generation of XUV vortices by HHG. In particular, we illustrate in detail the role of macroscopic phase matching of high-order harmonics when driven by OAM beams, which allows to control the production of attosecond beams carrying OAM.
关键词： attosecond helical beams,ultrafast phenomena,orbital angular momentum,attosecond pulses,extreme ultraviolet vortices,high harmonic generation,nonlinear optics,phase matching
更新于2025-09-09 09:28:46
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New Candidate Multicomponent Chalcogenide Glasses for Supercontinuum Generation
摘要： Broadband supercontinuum (SC) generation requires host material attributes defined by both optical and physical properties and the material’s manufacturability. We review and define the trade-offs in these attributes as applied to fiber or planar film applications based on homogeneous glass property data, and provide a series of examples of how one might optimize such attributes through material compositional and morphology design. As an example, we highlight the role of varying composition, microstructure, and linear/nonlinear optical properties, such as transmittance, refractive index, and the multiphoton absorption coefficient, for a series of novel multicomponent chalcogenide glasses within a model GeSe2-As2Se3-PbSe (GAP-Se) system. We report key optical property variation as a function of composition and form, and discuss how such glasses, suitable for both fiber and planar film processing, could lend themselves as candidates for use in SC generation. We demonstrate the impact of starting glass composition and morphology and illustrate how tailoring composition and form (bulk versus film) leads to significant variation in linear, nonlinear, and dispersive optical property behavior within this system that enables design options that are attractive to optimization of desirable SC performance, based on optical composites.
关键词： photonics,infrared optical materials,chalcogenide glass science,supercontinuum generation,nonlinear optics
更新于2025-09-09 09:28:46
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Dependence of the saturation intensity with the dopant ion concentration: Application to the study of nonlinear optical properties in Nd-doped phosphate glass matrix
摘要： The effect of ion concentration on the saturation intensity, Is, was investigated and its effect on the evaluation of nonlinear optical properties was discussed. The suggested experimental approach points out a more accurate way to obtain Is. The value of Is in the limit of low concentration and low incident intensity was obtained as (266 ± 14) KW/cm2 at 514 nm. Through time resolved Z-scan the nonlinear refractive index, n2, of Nd-doped phosphate glass could be evaluated for different Nd concentrations. Finally, the n2 and Is values were used to determine the polarizability difference between ground and excited states as Δα = (2.6 ± 0.2) × 10?26 cm3, for Nd3+ ions in this glass matrix.
关键词： Nonlinear optics,Optical materials,Amorphous materials
更新于2025-09-09 09:28:46
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Second harmonic spectroscopy of surface lattice resonances
摘要： Because of their large figures of merit, surface lattice resonances (SLRs) in metal nanoparticle arrays are very promising for chemical and biomolecular sensing, in both liquid and gas media. SLRs are sensitive to refractive index changes both near the surface of the nanoparticles (surface sensitivity) and in the volume between them (bulk sensitivity). Due to its intrinsic surface-sensitivity and a power-law dependence on electric fields, second harmonic generation (SHG) spectroscopy can improve upon both the surface and volume sensitivities of SLRs. In this report on SHG spectroscopy of plasmonic nanoparticles, we show that the SHG signal is greatly increased (up to 450 times) by the SLRs. We also demonstrate very narrow resonances in SHG intensity (~5 nm FWHM). We illustrate how the SHG resonances are highly sensitive to SLRs by varying the fundamental wavelength, angle of incidence, nanoparticle material and lattice constant of the arrays. Finally, we identify an SHG resonance (10 nm FWHM) that is electric dipole forbidden and can be attributed to higher-order multipoles, enhanced by the strong near-fields of SLRs. Our results open up new and very promising avenues for chemical and biomolecular sensing, based on SHG spectroscopy of SLRs.
关键词： Plasmonics,Quadrupoles,Nonlinear optics,Surface lattice resonance
更新于2025-09-09 09:28:46
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Dynamically Configurable Nonlinear Optical Switching Based on Vertically Aligned Carbon Nanotubes
摘要： The modification of the third order nonlinear optical response exhibited by vertically aligned carbon nanotubes in two-wave mixing interactions was analyzed. All-optical switching effects were explored by using a vectorial optical Kerr gate with nanosecond pulses at 532 nm wavelength of excitation. The samples were prepared by a spray pyrolysis method. Morphological and structural characterization of the samples was conducted by Scanning Electron Microscopy, Transmission Electron Microscopy and Raman Spectroscopy studies. Important structural changes dependent on the temperature employed for the preparation of the carbon nanotubes were observed. It was highlighted a remarkable influence of nonlinear energy transference in spatially-resolved optical processes for designing ultrafast low-dimensional devices.
关键词： aligned carbon nanotubes,Nonlinear Optics,Two-wave mixing
更新于2025-09-09 09:28:46
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Contents: (Adv. Funct. Mater. 48/2018)
摘要： New organic three-component single crystals exhibiting large macroscopic optical nonlinearity, excellent optical quality, and efficient optical-to-THz conversion are developed using so-called 'pseudo-isomorphic cocrystallization' for nonlinear optical and THz photonic applications.
关键词： THz photonics,pseudo-isomorphic cocrystallization,organic single crystals,nonlinear optics
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE Research and Applications of Photonics In Defense Conference (RAPID) - Miramar Beach, FL (2018.8.22-2018.8.24)] 2018 IEEE Research and Applications of Photonics In Defense Conference (RAPID) - Applications of Microwave Photonic Processing
摘要： We review recent advances in microwave photonic processors for full spectrum awareness and frequency translation. Hybrid integration progress for these systems is shown along with the latest waveguide and chip-scale technologies to reduce SWaP and improve performance.
关键词： Nonlinear optics,Subsystem integration and techniques,Radio frequency photonics,integrated optics,Integrated optics devices
更新于2025-09-04 15:30:14
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[OSA CLEO: QELS_Fundamental Science - San Jose, California (2015..-..)] CLEO: 2015 - Nonlinear Frequency Mixing in a Surface Nanoscale Axial Photonics Resonator
摘要： We report on four-wave mixing in a simple-to-fabricate surface nanoscale axial photonics resonator (SNAPR) obtained by pumping with two spectral modes while exploiting a self-locked pump scheme.
关键词： Microcavities,Nonlinear optics, four-wave mixing
更新于2025-09-04 15:30:14
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Hafnium Sulfide Nanosheets for Ultrafast Photonic Device
摘要： Group IVB transition metal dichalcogenides (TMDs) have attracted significant interests in photoelectronics due to their predictable superior physical properties compared to group VIB (Mo and W) TMDs. However, the nonlinear optical properties and ultrafast photonic devices based on group IVB TMDs remained unexplored so far. Herein, the nonlinear optical absorption of HfS2 nanosheets (NSs) prepared by liquid exfoliation is demonstrated. The usage of HfS2 as a new ultrafast photonic device for high-energy and ultrashort pulse generation in a fiber laser is reported for the first time. A photonic crystal fiber (PCF) assisted deposition method is presented for the fabrication of an HfS2-microfiber integrated saturable absorber (SA) device with precisely controllable light–matter interaction, which can benefit the output of the device. The HfS2-microfiber SA device shows modulation depth of 15.7% and exhibits outstanding ultrashort pulse generation performance with pulse duration of 221.7 fs in the communication band. The experimental results suggest that HfS2 presents highly nonlinear optical absorption and can be developed into an excellent candidate of SA devices for the development of HfS2-based ultrafast photonics.
关键词： nonlinear optics,hafnium sulfide,ultrafast photonics
更新于2025-09-04 15:30:14
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Zinc(II) as a Versatile Template for Efficient Dipolar and Octupolar Second-Order Nonlinear Optical Molecular Materials §
摘要： This short review outlines the main results obtained in the field of molecular materials based on zinc coordination compounds for second-order nonlinear optics. It presents an overview of the main classes of second-order nonlinear optical (NLO) active complexes bearing monodentate, bidentate, tridentate, or tetradentate π-delocalized ligands such as substituted stilbazoles, bipyridines, phenanthrolines, terpyridines, and Schiff bases. Macrocyclic ligands such as porphyrins and phthalocyanines are not covered. This paper shows how coordination to the Zn(II) center of π-delocalized nitrogen donor ligands produces a significant enhancement of their quadratic hyperpolarizability. Dipolar complexes are mainly presented, but octupolar zinc complexes are also presented. The coverage is mainly focused on NLO properties that are measured at the molecular level, working in solution, by means of the electric field-induced second harmonic generation (EFISH) or the hyper-Rayleigh scattering (HRS) techniques.
关键词： Zinc(II) complexes,EFISH,second-order nonlinear optics,HRS
更新于2025-09-04 15:30:14