We report the first experimental observation of three-dimensional light bullets, excited by femtosecond pulses in a system featuring quasi-instantaneous cubic nonlinearity and a periodic, transversally modulated refractive index. Stringent evidence of the excitation of light bullets is based on time-gated images and spectra which perfectly match our numerical simulations. Furthermore, we reveal a novel evolution mechanism forcing the light bullets to follow varying dispersion or diffraction conditions, until they leave their existence range and decay.

Plasmonic metamaterials exhibit strong and tunable dispersion, as a result of their pronounced resonances. This dispersion is used to construct an ultrathin light-shaping element that produces different waves at two distinct wavelengths in the near IR range. The optical response of the pixelated element is adjusted by variations in the geometry of the metamaterial's unit cell. Applications requiring spatial and spectral control of light become feasible.

We demonstrate a nonlinear optical chip that generates photons with reconfigurable nonclassical spatial correlations. We employ a quadratic nonlinear waveguide array, where photon pairs are generated through spontaneous parametric down-conversion and simultaneously spread through quantum walks between the waveguides. Because of the quantum interference of these cascaded quantum walks, the emerging photons can become entangled over multiple waveguide positions. We experimentally observe highly nonclassical photon-pair correlations, confirming the high fidelity of on-chip quantum interference. Furthermore, we demonstrate biphoton-state tunability by spatial shaping and frequency tuning of the classical pump beam.

We experimentally investigate coupling of the photoluminescence (PL) from monolayers of MoS2 to Mie-resonant metasurfaces consisting of silicon nanocylinders. By a systematic variation of the nanocylinder diameter, we sweep the metasurface resonances over the excitonic emission band of monolayer MoS2. We observe strong enhancement, as well as spectral and directional reshaping of the emission. By a comprehensive optical characterization, we unveil the different physical factors, including electronic, photonic, and mechanical influences, responsible for the observed PL changes. Importantly, we show that by geometrical tuning of the nanocylinder resonances, the emission can be tailored from occurring under very large angles to being directed out of the substrate plane. Our results highlight the need and potential of controlling not only the photonic, but also electronic and mechanical environmental factors for tailoring PL from TMD monolayers by integrating them in nanophotonic architectures.

Lateral heterostructures of dissimilar monolayer transition metal dichalcogenides provide great opportunities to build 1D in‐plane p–n junctions for sub‐nanometer thin low‐power electronic, optoelectronic, optical, and sensing devices. Electronic and optoelectronic applications of such p–n junction devices fabricated using a scalable one‐pot chemical vapor deposition process yielding MoSe2‐WSe2 lateral heterostructures are reported here. The growth of the monolayer lateral heterostructures is achieved by in situ controlling the partial pressures of the oxide precursors by a two‐step heating protocol. The grown lateral heterostructures are characterized structurally and optically using optical microscopy, Raman spectroscopy/microscopy, and photoluminescence spectroscopy/microscopy. High‐resolution transmission electron microscopy further confirms the high‐quality 1D boundary between MoSe2 and WSe2 in the lateral heterostructure. p–n junction devices are fabricated from these lateral heterostructures and their applicability as rectifiers, solar cells, self‐powered photovoltaic photodetectors, ambipolar transistors, and electroluminescent light emitters are demonstrated.