Plasmon-phonon coupling in large-area graphene dot and antidot arrays

Nanostructured graphene on SiO2 substrates pave the way for enhanced light-matter interactions and explorations of strong plasmon-phonon hybridization in the mid-infrared regime. Unprecedented large-area graphene nanodot and antidot optical arrays are fabricated by nanosphere lithography, with structural control down to the sub-100 nanometer regime. The interaction between graphene plasmon modes and the substrate phonons is experimentally demonstrated and structural control is used to map out the hybridization of plasmons and phonons, showing coupling energies of the order 20 meV. Our findings are further supported by theoretical calculations and numerical simulations.Comment: 7 pages including 6 figures. Supporting information is available upon request to author

275 Effects of ruxolitinib cream on sleep and quality of life over 52 weeks in black patients with atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease with phenotypic differences across race and can affect sleep and quality of life (QoL). In 2 phase 3 studies of identical design (TRuE-AD1/TRuE-AD2), patients (pts; ≥12 y with AD for ≥2 y; Investigator’s Global Assessment score 2/3; 3%–20% affected body surface area) were randomized (2:2:1) to twice-daily 0.75% or 1.5% ruxolitinib (RUX; Janus kinase [JAK]1/JAK2 inhibitor) cream or vehicle for 8 wk (continuous treatment), followed by a long-term safety period (LTS; as-needed treatment) up to Wk 52. Pts randomized to RUX cream remained on their regimen during the LTS; pts on vehicle were rerandomized to either RUX cream strength. For Black pts who were initially randomized to the 0.75% RUX cream/1.5% RUX cream/vehicle to 0.75% RUX cream/vehicle to 1.5% RUX cream groups and continued in the LTS (n=91/97/25/22), sleep-related impairment and sleep disturbance scores per Patient-Reported Outcomes Measurement Information System at baseline (BL) were 16.3/16.4/15.0/17.5 and 18.9/19.7/17.9/19.8, respectively. Scores had decreased (less impairment) at LTS start in the RUX cream groups (Wk 8; 14.2/14.7/16.1/15.5 and 16.7/17.5/19.0/19.4) and were below BL at Wk 52 in all groups (14.3/14.8/13.9/14.4 and 18.0/18.0/17.4/16.3). Dermatology Life Quality Index (DLQI) scores were decreased at Wk 8 (mean change from BL, −7.4/−6.6/−3.8/−4.8); decreased scores were maintained to Wk 52 (−7.1/−6.5/−5.6/−8.8). Results were similar for children’s DLQI (Wk 8, −4.0/−6.9/−4.0/−3.0 [n=12/9/1/3]; Wk 52, −5.6/−11.6/−12.0/−7.3 [n=9/7/1/4]). In summary, sleep and QoL improved with RUX cream; improvements were maintained for 44 wk with as-needed use in Black pts

287 Effects of ruxolitinib cream on pruritus in black patients with atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease that has phenotypic differences across race and can be more severe in Black patients. In two phase 3 identical design studies (TRuE-AD1/TRuE-AD2), patients (≥12 years old with AD for ≥2 years, Investigator’s Global Assessment [IGA] score 2/3, 3%–20% affected body surface area) were randomized (2:2:1) to twice-daily 0.75% or 1.5% ruxolitinib (Janus kinase [JAK]1/JAK 2 inhibitor) cream or vehicle for 8 weeks. Here we describe the effect of ruxolitinib cream on itch in Black patients using pooled data from the 2 studies (n=292). Mean itch numerical rating scale (NRS) score at baseline was 5.3/5.4 for ruxolitinib cream (0.75%/1.5%) and 5.7 for vehicle. Reductions in mean itch NRS score with ruxolitinib cream (0.75%/1.5%) were evident within approximately 12 hours of first application (–0.6/–0.7 vs −0.2 for vehicle), with statistically significant reductions by Day 4 vs vehicle (–1.4/–1.6 vs –0.6; both P\u3c0.05). For those with baseline itch NRS ≥4 (n=187; 64.0%), more patients achieved ≥4-point itch NRS improvement vs vehicle by Day 2 (6.1%/16.4% vs 0%); this increased to 15.9%/26.6% vs 3.0% on Day 7 and 30.1%/43.2% vs 17.5% at Week 8 (P=0.212/P=0.009). More patients applying 0.75%/1.5% ruxolitinib cream vs vehicle reported no days of itch per question 1 of the Patient-Oriented Eczema Measure (POEM) at Week 2 (19.0%/19.4% vs 5.3%); this increased at Week 8 (34.0%/30.8% vs 12.2%). In summary, ruxolitinib cream monotherapy over 8 weeks was associated with rapid and considerable itch relief in Black patients with AD

Resonant Visible Light Modulation with Graphene

Fast modulation and switching of light at visible and near-infrared (vis-NIR) frequencies is of utmost importance for optical signal processing and sensing technologies. No fundamental limit appears to prevent us from designing wavelength-sized devices capable of controlling the light phase and intensity at gigaherts (and even terahertz) speeds in those spectral ranges. However, this problem remains largely unsolved, despite recent advances in the use of quantum wells and phase-change materials for that purpose. Here, we explore an alternative solution based upon the remarkable electro-optical properties of graphene. In particular, we predict unity-order changes in the transmission and absorption of vis-NIR light produced upon electrical doping of graphene sheets coupled to realistically engineered optical cavities. The light intensity is enhanced at the graphene plane, and so is its absorption, which can be switched and modulated via Pauli blocking through varying the level of doping. Specifically, we explore dielectric planar cavities operating under either tunneling or Fabry-Perot resonant transmission conditions, as well as Mie modes in silicon nanospheres and lattice resonances in metal particle arrays. Our simulations reveal absolute variations in transmission exceeding 90% as well as an extinction ratio >15 dB with small insertion losses using feasible material parameters, thus supporting the application of graphene in fast electro-optics at vis-NIR frequencies.Comment: 17 pages, 13 figures, 54 reference

Egg retention and dispersal activity in the parasitoid wasp, Trichogramma principium

Effects of egg retention on movement and dispersal activity of Trichogramma principium (Hymenoptera, Trichogrammatidae) females were investigated under laboratory conditions. Individual females were observed during one minute in the absence of hosts. Movement activity and dispersal rate were estimated by the length of the track and by the distance from the start point, respectively. Before the test, all wasps during 2 – 4 days were presented with a possibility to parasitize a factitious laboratory host, Sitotroga cerealella Oliv. (Lepidoptera, Gelechiidae). Wasps that had parasitized before the test show significant reduction of spontaneous walking activity and dispersal rate when compared with females that refused to parasitize the non-preferred host (i.e. manifested egg retention). This effect cannot be considered as a direct arrestment reaction to the host because during the test period, no hosts were provided. Thus, egg retention results not only in temporal spread, but also in more intensive spatial dispersal of a group of simultaneously emerged females

Graphene on hexagonal boron nitride as a tunable hyperbolic metamaterial

Hexagonal boron nitride (h-BN) is a natural hyperbolic material1, in which the dielectric constants are the same in the basal plane (ε[superscript t] ≡ ε[superscript x] = ε[superscript y]) but have opposite signs (ε[superscript t] ε[superscript z ]< 0) in the normal plane (ε[superscript z]). Owing to this property, finite-thickness slabs of h-BN act as multimode waveguides for the propagation of hyperbolic phonon polaritons—collective modes that originate from the coupling between photons and electric dipoles in phonons. However, control of these hyperbolic phonon polaritons modes has remained challenging, mostly because their electrodynamic properties are dictated by the crystal lattice of h-BN. Here we show, by direct nano-infrared imaging, that these hyperbolic polaritons can be effectively modulated in a van der Waals heterostructure composed of monolayer graphene on h-BN. Tunability originates from the hybridization of surface plasmon polaritons in graphene with hyperbolic phonon polaritons in h-BN so that the eigenmodes of the graphene/h-BN heterostructure are hyperbolic plasmon–phonon polaritons. The hyperbolic plasmon–phonon polaritons in graphene/h-BN suffer little from ohmic losses, making their propagation length 1.5–2.0 times greater than that of hyperbolic phonon polaritons in h-BN. The hyperbolic plasmon–phonon polaritons possess the combined virtues of surface plasmon polaritons in graphene and hyperbolic phonon polaritons in h-BN. Therefore, graphene/h-BN can be classified as an electromagnetic metamaterial as the resulting properties of these devices are not present in its constituent elements alone

Graphene plasmonics

Two rich and vibrant fields of investigation, graphene physics and plasmonics, strongly overlap. Not only does graphene possess intrinsic plasmons that are tunable and adjustable, but a combination of graphene with noble-metal nanostructures promises a variety of exciting applications for conventional plasmonics. The versatility of graphene means that graphene-based plasmonics may enable the manufacture of novel optical devices working in different frequency ranges, from terahertz to the visible, with extremely high speed, low driving voltage, low power consumption and compact sizes. Here we review the field emerging at the intersection of graphene physics and plasmonics.Comment: Review article; 12 pages, 6 figures, 99 references (final version available only at publisher's web site

LOFAR Detection of 110-188 MHz Emission and Frequency-Dependent Activity from FRB 20180916B

FRB 20180916B is a well-studied repeating fast radio burst source. Its proximity (~150 Mpc), along with detailed studies of the bursts, have revealed many clues about its nature -- including a 16.3-day periodicity in its activity. Here we report on the detection of 18 bursts using LOFAR at 110-188 MHz, by far the lowest-frequency detections of any FRB to date. Some bursts are seen down to the lowest-observed frequency of 110 MHz, suggesting that their spectra extend even lower. These observations provide an order-of-magnitude stronger constraint on the optical depth due to free-free absorption in the source's local environment. The absence of circular polarization and nearly flat polarization angle curves are consistent with burst properties seen at 300-1700 MHz. Compared with higher frequencies, the larger burst widths (~40-160 ms at 150 MHz) and lower linear polarization fractions are likely due to scattering. We find ~2-3 rad/m^2 variations in the Faraday rotation measure that may be correlated with the activity cycle of the source. We compare the LOFAR burst arrival times to those of 38 previously published and 22 newly detected bursts from the uGMRT (200-450 MHz) and CHIME/FRB (400-800 MHz). Simultaneous observations show 5 CHIME/FRB bursts when no emission is detected by LOFAR. We find that the burst activity is systematically delayed towards lower frequencies by ~3 days from 600 MHz to 150 MHz. We discuss these results in the context of a model in which FRB 20180916B is an interacting binary system featuring a neutron star and high-mass stellar companion.Comment: Accepted for publication by ApJ