"Nonperturbative Nonlinearities": Perhaps Less than Meets the Eye.

We address challenges in characterizing changes in permittivity and refractive index beyond standard perturbative methods with special attention given to transparent conductive oxides (TCOs). We unveil a realistic limit to permittivity changes under high optical power densities. Our study covers both slow and ultrafast nonlinearities, demonstrating that all nonlinearities induce refractive index changes accurately described by a simple curve with saturation electric field (or irradiance) and maximum change of permittivity at saturation.

Idiopathic Epilepsy Risk Allele Trends in Belgian Tervuren: A Longitudinal Genetic Analysis.

Idiopathic epilepsy (IE) has been known to be inherited in the Belgian Tervuren for many decades. Risk genotypes for IE in this breed have recently been identified on Canis familiaris chromosomes (CFA) 14 and 37. In the current study, the allele frequencies of these loci were analyzed to determine whether dog breeders had employed a purposeful selection against IE, leading to a reduction in risk-associated allele frequency within the breed over time.

New Horizons in Near-Zero Refractive Index Photonics and Hyperbolic Metamaterials.

The engineering of the spatial and temporal properties of both the electric permittivity and the refractive index of materials is at the core of photonics. When vanishing to zero, those two variables provide efficient knobs to control light-matter interactions. This Perspective aims at providing an overview of the state of the art and the challenges in emerging research areas where the use of near-zero refractive index and hyperbolic metamaterials is pivotal, in particular, light and thermal emission, nonlinear optics, sensing applications, and time-varying photonics.

Canine reference genome accuracy impacts variant calling: Lessons learned from investigating embryonic lethal variants.

Deficient homozygosity of a variant maintained in a population suggests that the variant may be embryonic lethal. We examined whole genome sequence data from 675 canids to investigate for variants with missing homozygosity and high predicted impact. Our analysis identified 45 variants, in 32 genes.

On-chip integrated quantum emitter with 'trap-enhance-guide': a simulation approach.

To address the challenges of developing a scalable system of an on-chip integrated quantum emitter, we propose to leverage the loss in our hybrid plasmonic-photonic structure to simultaneously achieve Purcell enhancement as well as on-chip maneuvering of nanoscale emitter via optical trapping with guided excitation-emission routes. In this report, we have analyzed the feasibility of the functional goals of our proposed system in the metric of trapping strength (∼8KT), Purcell factor (>1000∼), and collection efficiency (∼10%). Once realized, the scopes of the proposed device can be advanced to develop a scalable platform for integrated quantum technology.

Optimizing epsilon-near-zero based plasmon assisted modulators through surface-to-volume ratio.

Plasmonic-based integrated nanophotonic modulators, despite their promising features, have one key limiting factor of large insertion loss (IL), which limits their practical potential. To combat this, we utilize a plasmon-assisted approach through the lens of surface-to-volume ratio to realize a 4-slot based EAM with an extinction ratio (ER) of 2.62 dB/µm and insertion loss (IL) of 0.

Developing momentum in vanishing index photonics.

Refractive index invariably describes the speed at which light passes through materials, and subsequently its perceived momentum. But what happens to these quantities as the index becomes zero? A new work explores this question, highlighting how momentum in near-zero-index materials affects linear optical processes.

Enhancing student scientific literacy through participation in citizen science focused on companion animal behavior.

The Covid-19 pandemic served as the impetus to implement activities designed to engage students in the remote instructional environment while simultaneously developing scientific literacy skills. In a high enrollment general education animal science course, numerous activities were designed to improve scientific literacy. These included specifically developed videos covering strategies for reading published science literature, the utilization of topically relevant scientific articles that captured student interest, and engaging students in a citizen science exercise on whether dogs align themselves to the Earth's magnetic field during excretion behavior.

Plasmonic colors in titanium nitride for robust and covert security features.

A mechanically robust metasurface exhibiting plasmonic colors across the visible and the near-IR spectrum is designed, fabricated, and characterized. Thin TiN layers (41 nm in thickness) prepared by plasma-enhanced atomic layer deposition (ALD) are patterned with sub-wavelength apertures (75 nm to 150 nm radii), arranged with hexagonal periodicity. These patterned films exhibit extraordinary transmission in the visible and the near-IR spectrum (550 nm to 1040 nm), which is accessible by conventional Si CCD detectors.

Low-loss plasmon-assisted electro-optic modulator.

For nearly two decades, researchers in the field of plasmonics -which studies the coupling of electromagnetic waves to the motion of free electrons near the surface of a metal -have sought to realize subwavelength optical devices for information technology, sensing, nonlinear optics, optical nanotweezers and biomedical applications . However, the electron motion generates heat through ohmic losses. Although this heat is desirable for some applications such as photo-thermal therapy, it is a disadvantage in plasmonic devices for sensing and information technology and has led to a widespread view that plasmonics is too lossy to be practical.

Corrigendum: Controlling hybrid nonlinearities in transparent conducting oxides via two-colour excitation.

This corrects the article DOI: 10.1038/ncomms15829.

Controlling hybrid nonlinearities in transparent conducting oxides via two-colour excitation.

Nanophotonics and metamaterials have revolutionized the way we think about optical space (ɛ,μ), enabling us to engineer the refractive index almost at will, to confine light to the smallest of the volumes, and to manipulate optical signals with extremely small footprints and energy requirements. Significant efforts are now devoted to finding suitable materials and strategies for the dynamic control of the optical properties. Transparent conductive oxides exhibit large ultrafast nonlinearities under both interband and intraband excitations.

High-Performance Doped Silver Films: Overcoming Fundamental Material Limits for Nanophotonic Applications.

The field of nanophotonics has ushered in a new paradigm of light manipulation by enabling deep subdiffraction confinement assisted by metallic nanostructures. However, a key limitation which has stunted a full development of high-performance nanophotonic devices is the typical large losses associated with the constituent metals. Although silver has long been known as the highest quality plasmonic material for visible and near infrared applications, its usage has been limited due to practical issues of continuous thin film formation, stability, adhesion, and surface roughness.

Enhanced Nonlinear Refractive Index in ε-Near-Zero Materials.

New propagation regimes for light arise from the ability to tune the dielectric permittivity to extremely low values. Here, we demonstrate a universal approach based on the low linear permittivity values attained in the ε-near-zero (ENZ) regime for enhancing the nonlinear refractive index, which enables remarkable light-induced changes of the material properties. Experiments performed on Al-doped ZnO (AZO) thin films show a sixfold increase of the Kerr nonlinear refractive index (n_{2}) at the ENZ wavelength, located in the 1300 nm region.

Adiabatically tapered hyperbolic metamaterials for dispersion control of high-k waves.

Hyperbolic metamaterials (HMMs) have shown great promise in the optical and quantum communities due to their extremely large, broadband photonic density of states. This feature is a direct consequence of supporting photonic modes with unbounded k-vectors. While these materials support such high-k waves, they are intrinsically confined inside the HMM and cannot propagate into the far-field, rendering them impractical for many applications.

Refractory plasmonics with titanium nitride: broadband metamaterial absorber.

A high-temperature stable broadband plasmonic absorber is designed, fabricated, and optically characterized. A broadband absorber with an average high absorption of 95% and a total thickness of 240 nm is fabricated, using a refractory plasmonic material, titanium nitride. This absorber integrates both the plasmonic resonances and the dielectric-like loss.

Experimental demonstration of titanium nitride plasmonic interconnects.

An insulator-metal-insulator plasmonic interconnect using TiN, a CMOS-compatible material, is proposed and investigated experimentally at the telecommunication wavelength of 1.55 µm. The TiN waveguide was shown to obtain propagation losses less than 0.

Towards CMOS-compatible nanophotonics: ultra-compact modulators using alternative plasmonic materials.

We propose several planar layouts of ultra-compact plasmonic modulators that utilize alternative plasmonic materials such as transparent conducting oxides and titanium nitride. The modulation is achieved by tuning the carrier concentration in a transparent conducting oxide layer into and out of the plasmon resonance with an applied electric field. The resonance significantly increases the absorption coefficient of the modulator, which enables larger modulation depth.

Sustained antibody-dependent cell-mediated cytotoxicity (ADCC) in SIV-infected macaques correlates with delayed progression to AIDS.

Although several in vitro lines of evidence support the potential power of antibody-dependent cell-mediated cytotoxicity (ADCC) in controlling HIV infection, the role of ADCC in the pathogenesis of HIV infection in vivo remains uncertain. There are few studies to date that longitudinally determine the plasma ADCC activity in HIV-infected subjects. We sought to establish an SIV/macaque model to perform such a longitudinal study.

Antigenic variation of SIV: mutations in V4 alter the neutralization profile.

Antigenic variation is a characteristic feature of lentiviral infection. The SIV/macaque model of AIDS provides an ideal system in which to investigate the molecular basis of antigenic variation. The purpose of this study was to genetically map the nucleotide changes in env that alter the neutralization phenotype of SIV.

Nucleotide sequence of a 13.9 kb segment of the 90 kb virulence plasmid of Salmonella typhimurium: the presence of fimbrial biosynthetic genes.

The 90kb plasmid resident in Salmonella typhimurium confers increased virulence in mice by promoting the spread of infection after invasion of the intestinal epithelium. The nucleotide sequence of a 13.9kb segment of this plasmid known to encode an outer membrane protein related in sequence to components of fimbrial biosynthesis in enteric bacteria was determined.