We study numerically and experimentally the dynamics control of viscous fingering patterns in a circular Hele-Shaw cell. The nonlocality nonlinearity system, especially interactions among developing fingers, make emergent pattern difficult to predict control. By controlling injection rate less fluid, we can precisely suppress evolving interfacial instabilities. There exist denumerable attractive, self-similarly symmetric, universal shapes. Experiments confirm feasibility strategy, which is...

Information display utilizing plasmonic color generation has recently emerged as an alternative paradigm to traditional printing and technologies. However, many implementations so far have either presented static pixels with a single state or rely on relatively slow switching mechanisms such chemical transformations liquid crystal transitions. Here, we demonstrate spatial, spectral, temporal control of light using dynamic that function through the electric-field-induced alignment nanorods in...

A nanoparticle (NP) doping technique was developed for fabricating erbium (Er)- and holmium (Ho)-doped silica-based optical fibers high energy lasers. Slope efficiencies in excess of 74% were realized Er NP a single mode fiber based master oscillator power amplifier (MOPA) 53% with multi-Watt-level output resonantly cladding-pumped laser configuration on double-clad fiber. Cores comprising Ho doped LaF3 Lu2O3 nanoparticles exhibited slope as 85% at 2.09 µm configuration. To the best authors'...

We introduce a graphene oxide/gold nanorod nanocomposite as surface-enhanced Raman spectroscopy (SERS) substrate that suppresses the usual temporal intensity fluctuations, commonly referred to blinking. The stability of SERS spectra from is statistically determined using coefficient variation integrated spectra. demonstrate that, by introducing oxide, five times smaller when compared gold nanorods without which attributed removal nanorod's surfactant plasmonic hot spots due oxide–surfactant...

The electric field controlled alignment of gold nanorods offers a paradigm for anisotropic molecules with the potential wide variety phases and structures. We experimentally study optical absorption from nanorod suspensions aligned using external fields. show that these depends linearly on orientational order parameter. provide evidence critical needed to orient is proportional volume depolarization anisotropy. Utilizing this dependence, we demonstrate two different sizes each population can...

We demonstrate an average surface-enhanced Raman scattering enhancement on the order of 108 from benzenethiol molecules using self-assembled, macroscopic, and tunable gold nanosphere monolayers non-templated substrates. The self-assembly uses a simple efficient technique that allows for creation high-density, chemically functionalized with factors comparable to those produced top-down fabrication techniques. These films may provide approach future development portable chemical/biological sensors.

The ability to tune the resonant frequency in plasmonic nanostructures is fundamental developing novel optical properties and ensuing materials. Recent theoretical insights have shown through conductive concatenation of nanoparticles that effective depolarization factor nanostructure, subsequent charge transfer plasmon (CTP) resonance, can be intricately controlled [Fontana, J.; Ratna, B. R. Appl. Phys. Lett. 2014, 105, 011107]. However, translating these from proof-of-principle experiments...

A self‐assembled metamaterial exhibiting a positive near‐zero index of refraction at visible wavelengths is demonstrated. The consists thiolene‐functionalized gold nanospheres into macroscopic, crosslinked, monolayers. By measuring the real and imaginary parts phase shift light transmitted through films effective determined as function wavelength. These findings may pave way to simply efficiently self‐assemble optically characterize multifunctional, multilayer nanoparticle–ligand metamaterials.

The assembly of plasmonic nanoparticles with precise spatial and orientational order may lead to structures new electromagnetic properties at optical frequencies. directed self‐assembly method presented controls the interparticle‐spacing symmetry resulting nanometer‐sized elements in solution. three‐dimensional (3D), icosahedral nanosclusters (NCs) resonances visible wavelengths is demonstrated experimentally. ideal NCs consist twelve gold (Au) nanospheres (NSs) attached thiol groups...

Abstract Rapid development of DNA technology has provided a feasible route to creating nanoscale materials. acts as self‐assembled nanoscaffold capable assuming any three‐dimensional shape. The ability integrate dyes and new optical materials such quantum dots plasmonic nanoparticles precisely onto these architectures provides ways exploit their near‐ far‐field interactions. A fundamental understanding processes will help drive next‐generation photonic nanomaterials. This review is focused...

A simple method for the fabrication of nanocomposite materials using thiol click chemistry is reported. The produced each displayed distinctive colors which were found to be dependent on both ligand used functionalize nanoparticles and concentration in materials. Functionalized metallic nanospheres combined with solutions forming viscous prepolymer then polymerized upon UV light exposure. Films fabricated a custom-built film mold, microfibers hydrodynamic focusing microfluidic channel. For...

We study the optical properties of gold nanorod (Au NR) dimers connected end-to-end by a thin metallic junction. The plasmonic oscillations along long axis dimer gives rise to two dominant modes: bonding plasmon emerging from dipolar mode each individual and charge transfer involving entire structure. find absorbance peak shift structure is proportional NR aspect ratio (AR) behaving as it was single with an AR nearly order magnitude larger. sensitively depends on material geometry connecting...

The index of refraction governs the flow light through materials. At visible and near infrared wavelengths real part refractive is limited to less than 3 for naturally occurring transparent materials, fundamentally restricting applications. Here, we carried out experiments study upper limit effective self-assembled metasurfaces at near-infrared wavelengths. centimeter-scale were made a hexagonally close packed (hcp) monolayer gold nanospheres coated with tunable alkanethiol ligand shells,...

Abstract The emergence of metamaterials (MMs) has led to groundbreaking photo-physical phenomena, which arise from their novel structure-dependent properties. Consisting “meta-atom” building blocks, MMs can be organized into subwavelength metal/dielectric structures using bottom-up or top-down nanofabrication techniques. Optical metal metasurfaces are a class with macroscopic lateral dimensions but composed one few layers precisely oriented metal-based elements over large surface area. In...

As information technologies move from electron-to photon-based systems, the need to rapidly modulate light is of paramount importance. Here, we study evolution electric-field-induced ali ...

Abstract Infrared plasmonic nanoantennas are key building blocks in nanotechnology. By coupling and confining light into spatial volumes below the diffraction limit, infrared provide unique opportunities to sense signal at nanometer length scales for energy harvesting, as sources, nanomedicine applications. However, contrast their radio‐ microwave counterparts, widespread use of has been limited, due part inability synthesize these structures maintaining nanoscale precision large batches...

Synthetic DNA templated nanostructures offer an excellent platform for the precise spatial and orientational positioning of organic inorganic nanomaterials.

We created centimeter-scale area metasurfaces consisting of a quasi-hexagonally close packed monolayer gold nanospheres capped with alkanethiol ligands on glass substrates using directed self-assembly approach. experimentally characterized the morphology and linear nonlinear optical properties metasurfaces. show these metasurfaces, interparticle gaps 0.6 nm, are modeled well classical (without charge transfer) description. find large dispersion refractive index, ranging from values less than...

A large third-order nonlinear susceptibility was measured at 1500 nm from a self-assembled metasurface composed of 2D superlattice ligand-capped gold nanospheres. self-defocusing refractive index (n2=−1.05×10−10 cm2 W−1) and absorption coefficient (α2=3.00×10−6 cm were determined using the Z-scan technique with 70 fs pulses 1 kHz. The nonlinearity response time to be 1.42 ps an Optical Kerr Gate configuration. n2 value is four orders magnitude larger, in modulus, than silica glass substrate...

A nanoparticle (NP) doping technique was used for making erbium-doped fibers (EDFs) high energy lasers. The nanoparticles were doped into the silica soot of preforms, which drawn fibers. Er luminescence lifetimes NP-doped cores are longer than those corresponding solution-doped silica, and substantially less Al is incorporated cores. Optical-to-optical slope efficiencies greater 71% have been measured. Initial investigations stimulated Brillouin scattering (SBS) indicated that SBS...

The St. Petersburg paradox provides a simple paradigm for systems that show sensitivity to rare events. Here, we demonstrate physical realization of this using tensile fracture, experimentally verifying six decades spatial and temporal data two different materials the fracture force depends logarithmically on length fiber. model may be useful in variety fields where failure reliability are critical.

We demonstrate the digital electric field induced switching of plasmonic nanorods between “1” and “0” orthogonal aligned states using an electro-optic fluid fiber component. show by digitally that thermal rotational diffusion can be circumvented, demonstrating approach to achieve submicrosecond times. also show, from initial unaligned state, into applied direction in 110 ns. The high-speed integrated all-fiber optical component may provide opportunities for remote sensing signaling applications.