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Hybridized nanostructures composed by metals and dielectrics, semiconductors or organics offer new opportunities achieving new functionalities in nonlinear optics, plasmonics, sensing [1-4]. In particular GaAs-AlGaAs-GaAs core-shell-supershell nanowires (NWs) fabricated by self-catalyzed growth on Si substrates were partially covered with gold, thus producing a symmetry breaking in the sample geometry...
Optical rectification of ultrashort laser pulses in electro-optic crystals is an established technique of terahertz generation. In this technique, the pump optical pulse produces a nonlinear polarization that moves with the group velocity of the optical pulse and acts as a source of terahertz radiation. The up-to-date generation schemes based on this principle utilize both the standard collinear phase...
The nonlinear light-matter interaction lies at the heart of controlling the electronic systems for the purpose of developing ultrafast optical switching and modulation devices [1], and attosecond laser technology [2]. In general, the interaction causes the formation of photon dressed state that is a quantum superposition state with energetically spaced sidebands and enables to generate the phase-locked...
Two-dimensional transition metal dichalcogenide (MX2) are receiving lot of attention in recent years due to their excellent electronic and optical properties which make them feasible for advanced photonics applications [1]. In particular Molybdenum-Disulfide (MoS2) has shown large exciton binding energy, strong spin-orbit interaction, and high carrier mobilities.
Fibers are considered as extraordinary tabletop laboratories to investigate optical turbulence and optical rogue waves (ORW). However ultrafast measurement of random optical power fluctuations is a challenging experimental task and the typical sub-picosecond timescale prevented-up to now-time-resolved observations of the awaited dynamics. We report the first single-shot recordings of ORW emerging...
The nonlinear properties of colloidal suspensions of dielectric nanoparticles (nanocolloids) were recognized since the 1980's [1]. Nevertheless, this topic has attracted renewed interest in recent years due to the progress in the synthesis capabilities and applications of nanoparticles. In the case of dielectric nanoparticles, the colloidal medium exhibits a Kerr-like nonlinearity produced by the...
In recent years, the fabrication, structural modification and characterisation of nanostructured materials have gained a great deal of attention due to their distinctive properties and potential use in technological applications. Glass containing silver (Ag) nanoparticles (NP), or Metal-Glass Nanocomposite (MGN), is routinely used as high-contrast optical polarisers [1], and has been recently shown...
High-order harmonic generation (HHG) in atomic gases is one of the key phenomena in strong-field laser-matter interactions, playing a central role in optical physics and rapidly growing attosecond technologies. When applied to solid materials [1-3], approaches of strong-field physics are subject to natural limitations, related to absorption and much lower laser damage thresholds of solids. As a reward,...
We report on a novel phenomenon: an intense circularly polarized infrared laser pulse induces a transient chirality in an achiral transparent dielectric. In contrast to the well-known optical Faraday effect in atomic vapours [1], this effect occurs far from resonant transitions — we consider the case where a uniaxial dielectric crystal (sapphire) is transparent to light. We show how the build-up and...
Combining nanostructures in metamaterials allows precise engineering not only their linear optical properties and dispersion but also the nonlinear response and dynamic optical properties [1, 2]. In particular, hyperbolic metamaterials, based on plasmonic nanorod arrays or metal-dielectric multilayers, provide wealth of exciting possibilities in nonlinear optics offering designed linear and nonlinear...
Metallic colloids can confine and focus light below the diffraction limit, leading to interesting properties and applications, such as metamaterials and sensors. However, accurate knowledge of the refractive indices of these colloids is critical to develop their unique optical properties. Anisotropic colloids, such those with Au nanorods (NRs) can be aligned with external electric fields, thus dynamically...
Control of light propagation is usually obtained by appropriately designing the optical path, that is, the refractive index of the material. Common examples are standard lenses and dielectric waveguides. Recently, a new way to tailor the wave front emerged, based on the Pancharatnam-Berry phase (PBP). The PBP is a geometric phase related to changes in the polarization state of light along its propagation...
A new branch of nonlinear nanophotonics based on high refractive index dielectric nanoparticles is emerging [1]. The unique large resonant enhancement of both electric and magnetic fields associated with very low dissipative losses considerably increases optical interactions at sub-wavelength scales opening new unexplored functionalities. Recently, AlGaAs nanodisks enabled second harmonic generation...
Metamaterials and metasurfaces are artificial structures whose optical properties go beyond the natural behaviour of light. Their appeal revolves around the possibility to design the optical response by changing the geometry of the structure using essentially the same material constituents [1]. Some classes of metamaterials and metasurfaces can be fabricated over macroscopic areas and have strong...
Recently, the concept of the geometric Pancharatnam-Berry (P-B) phase has been successfully extended to optical metasurfaces operating in the nonlinear regime1–3. It was shown that the nonlinear geometric P-B phase of each meta-atom is determined by the spin of the fundamental wave, the spin of the nonlinear signal, and the order of the nonlinear process1. By manipulating the interferences of SHG...
It is well known that the nonlinear response of bound electrons in transparent solids occurs on a very fast time scale. Recently, a significant delay of the nonlinear response in the regime of intense (close to the materials damage threshold) femtosecond laser fields was reported [1]. In the regime of weak laser fields, where the response is dominated by the third-order nonlinearity, it is known since...
Nonperturbative electron dynamics inside of solids under strong optical fields has recently found particular attention. Light-field driven effects such as high-harmonic generation and sub-optical-cycle interband population transfer have been reported for dielectrics and semiconductors. However, much less is known about strong-field phenomena in conducting materials. Graphene is an ideal playground...
In optical metasurfaces, disorder, e.g. in the arrangement or shape of its building blocks, is usually associated with a deterioration of the optical properties due to an increase of incoherent scattering. However, more recently, researchers have started recognizing the introduction of controlled disorder as a strategy to diversify engineering options of metasurfaces. For example, the introduction...
Recently we investigated cascaded schemes for down-conversion to the mid-IR spectral range above 5 μm by implementing the second stage based on a non-oxide nonlinear crystal inside the cavity of a ns optical parametric oscillator (OPO) based on Rb:PPKTP, pumped by a Q-switched Nd:YAG laser [1-3]. Intracavity difference-frequency generation (DFG) [2, 3] turned out to be more efficient compared to intracavity...
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