相关论文: Effective Second Order Susceptibility in Photonic …
We consider conditions under which photonic crystals (PCs) can be homogenized in the higher photonic bands and, in particular, near the $\Gamma$-point. By homogenization we mean introducing some effective local parameters $\epsilon_{\rm…
In this paper we study numerically and experimentally the possibility of using metallic photonic crystals (PCs) of different geometries (log-piles, direct and inverse opals) as visible light sources. It is found that by tuning geometrical…
The ability to engineer metamaterials with tunable nonlinear optical properties is crucial for nonlinear optics. Traditionally, metals have been employed to enhance nonlinear optical interactions through field localization. Here, inspired…
Chirality is a pervasive form of symmetry that is intimately connected to the physical properties of solids, as well as the chemical and biological activity of molecular systems. However, its control with light is challenging, because…
In this study, we present the design of a photonic crystal (PC) structure with a hexagonal lattice, where adjustments to the PC unit cell symmetry reveal an all-angle self-collimation (SC) effect. By optimizing opto-geometric parameters,…
Second-order nonlinear optical processes do not manifest in the bulk of centrosymmetric materials, but may occur in the angstroms-thick layer at surfaces. At such length-scales, quantum mechanical effects come into play which could be…
Second harmonic generation is a powerful tool directly connected to the symmetry of materials. Phase transitions, lattice rotations or electromagnetic coupling in multiferroic compounds can be revealed by using second harmonic…
We study the nonlinear process of second harmonic generation in photonic time-crystals, materials with refractive index that varies abruptly and periodically in time, and obtain the phase matching condition for this process. We find…
The use of biomaterials - with techniques such as DNA-directed assembly or bio-directed synthesis - can surpass top-down fabrication techniques in creating plasmonic superstructures, in terms of spatial resolution, range of functionality…
Non-resonant second harmonic generation phase and amplitude measurements obtained from the silica:water interface at varying pH and 0.5 M ionic strength point to the existence of a nonlinear susceptibility term, which we call chi(3)X, that…
Quasicrystals are unique materials characterized by long-range order without periodicity. They are observed in systems such as metallic alloys, soft matter, and particle simulations. Unlike periodic crystals, which are invariant under…
To a significant extent, the rich physical properties of photonic crystals are determined by the underlying geometry, in which the composed symmetry operators and their combinations contribute to the unique topological invariant to…
Organic molecular crystals are appealing for next-generation optoelectronic applications, most notably due to their multiexciton generation process that can increase the efficiency of photovoltaic devices. However, a general understanding…
The development of nanomaterials with a large nonlinear susceptibility is essential for nonlinear nanophotonics. We show that transition-metal-dichalcogenide (TMD) nanotriangles have a large effective second-order susceptibility…
The enhanced nonlinear optical response of a one-dimensional (1D) photonic crystal (PC) made from polymers and graphene composites is observed. The graphene PC was fabricated by spin-coating. It shows obvious bandgaps at two wavelengths in…
Second harmonic generation (SHG) is forbidden in centrosymmetric molecular materials. However, a signal is frequently observed from interfaces where the symmetry is broken. Whereas the effect can be phenomenologically accommodated, an ab…
Introducing symmetry breaking in materials enables the emergence of functionalities. This can be microscopically and macroscopically driven by applying external stimuli such as mechanical stress, electric field, temperature, and chemical…
Non-invasive optical manipulation of particles has emerged as a powerful and versatile tool for biological study and nanotechnology. In particular, trapping and rotation of cells, cell nuclei and sub-micron particles enables unique…
We present a study on photonic vertical cavities consisting of nonlinear materials embedded in photonic crystals (PhCs) for resonantly enhancing second harmonic generation (SHG). Previous attempts at SHG in such structures have been limited…
In this work, a doubly resonant photonic crystal (PhC) cavity using the merged bound states in the continuum (BICs) is proposed to obtain a higher second harmonic generation (SHG) efficiency. Firstly by scanning geometry parameters the…