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A high-contrast and compact wavelength diplexer is presented for conventional 1550 nm and emerging 2000 nm based on a subwavelength-grating (SWG) coupler. The SWG silicon waveguide thoroughly blocks the light propagation around 1550 nm but fully supports 2000 nm (extinction ratio: 43.11 dB). This grating type anisotropic metamaterial not only efficiently reduces the coupling length but also expands the operational bandwidth. Simulated by 3D finite-difference time-domain method, the proposed diplexer possesses a remarkably low insertion loss and a high contrast of 25.24 (31.7) dB at 1550 (2000) nm. The operational bandwidth of 200 (108) nm is achieved with contrast over 15 dB and insertion loss below 0.22 dB. The footprint of diplexer is only 5.27 μm × 11.85 μm. Moreover, such design has the scalability by simply tuning the geometrical parameters of SWG.

The autostereoscopic 3D display has two important indicators, both the number of viewpoints and display resolution. However, it's a challenge to improve both the viewpoint and the resolution. Here, we develop a fixed-position multiview and lossless resolution autostereoscopic 3D display system that includes the dynamic liquid crystal (LC) grating screen. This display system consists of an LC display panel and an LC grating screen. The synchronization of the frame switching of the LC display panel and the LC grating screen shutter enables the preserved resolution. The “eye space” design makes the viewpoint dense enough and determines the LC grating screen's parameters. We use binocular viewpoint tracking technology to realize the LC grating screen's adaptive control based on the above work. Different binocular views are rendered in real-time according to the different positions of a single pair of stereoscopic viewpoints in the eye space, making the motion parallax possible. We present the working principle and mathematical analysis. We implement a prototype for verifying the principle. According to the experiment results analysis, this prototype can achieve viewpoint tracking and motion parallax based on resolution lossless and viewpoint dense enough.

In this letter, we propose ultra-compact TE-polarized even-to-odd mode converter designs by introducing Ge/Si patterns into silicon waveguide-integrated functional region. The Ge areas with continuous boundaries are determined by topology optimization that combines finite element method, geometric projection method, and method of moving asymptotes. Both two-dimensional (2D) and quasi-3D designs are presented. Simultaneous beam splitting and phase shifting are achieved in the functional region with only $1.0 \times 1.55\;{\rm{\mu }}{{\rm{m}}^2}$ area. Based on the 3D finite-difference time-domain simulations, the quasi-3D designs possess satisfactory mode purity (>0.99) at center wavelength 1550 nm, and the mode purity keeps higher than 0.92 within the wavelength range from 1500 to 1600 nm. Meanwhile, the forward transmission efficiency is shown higher than 0.89 within the operational bandwidth. Moreover, the robustness is demonstrated by considering the loss of Ge material and the geometric deviations. The proposed mode-order converters bring together advantages including wavelength footprint, high mode purity, low insertion loss, and large operational bandwidth.

In this paper, we systematically investigate the structural and electronic properties of Janus transition metal dichalcogenide bilayers using first-principles calculations. 2H phase Janus MXY (M = Mo, W; X, Y=S, Se, Te) bilayers with five possible stacking types are focused. The energetically favorable stacking type and the corresponding gap between layers are determined by comparing binding energies with van der Waals interaction. The Janus MXY bilayers with this specific stacking are indirect semiconductors with bandgaps ranging from 0.014 eV to 0.932 eV, which are smaller compared with their monolayers. The valence band maximums of MoSeTe, WSSe and WSeTe bilayers locate at high-symmetry K point while the conduction band minimums of all bilayers except MoSSe move to the position between K and Γ. Moreover, the electronic band structures of total 30 possible Janus TMD bilayers are demonstrated, presenting a promising platform for nanoscale electronic and optoelectronic devices.

EXECUTIVE SUMMARY In this study, the authors used simulation to explore factors that might influence hospitals' decisions to adopt evidence-based interventions. Specifically, they developed a simulation model to examine the extent to which hospitals would benefit economically from the transitional care model (TCM). The TCM is designed to transition high-risk older adults from hospitals back to communities using interventions focused on preventing readmissions.The authors used qualitative methods to identify and validate simulation facets. Four simulation experiments explored the economic impact of the TCM on more than 3,000 U.S. hospitals: (1) magnitude of readmission penalty, (2) application to specific diagnosis-related groups, (3) level of cost sharing between payer and provider, and (4) capitated versus fee-for-service payments. The simulator projected hospital-specific economic effects. The authors used Monte Carlo methods for the simulations, which were parameterized with public data sets from the Centers for Medicare & Medicaid Services (CMS) and TCM data from randomized controlled trials and comparative effectiveness studies.Under current conditions, the simulation indicated that only 10 of more than 3,000 Medicare-certified hospitals would benefit financially from the TCM. If current readmission penalties were doubled, the number of hospitals projected to benefit would increase to 300. Targeting selected diagnosis cohorts would also increase the number of hospitals to 300. If payers reimbursed providers for 100% of the TCM costs, 2,000 hospitals would benefit financially. Under a capitated payment model, 1,500 hospitals would benefit from the TCM.Current CMS penalties-or reasonable increases-have little economic effect on the TCM. In the current environment, two strategies are likely to facilitate adoption: (1) persuading payers to reimburse TCM costs and (2) focusing on hospitals with higher bed occupancies and higher revenue patients.

We propose and numerically demonstrate a design of bidirectional transverse electric (TE) polarized mode-order converter based on silicon-on-insulator platform. This converter is realized by introducing high refractive index material inlaid in a silicon slab waveguide. Simulated by three-dimensional finite-difference method time-domain, the forward (TE0 to TE1-like conversion) transmittance reaches approximately 88.2%, while the backward value (TE1 to TE0-like conversion) is about 89.4% at the wavelength of 1550 nm. The footprint of this converter is as small as 0.95 × 1.5 μm2. Fabrication tolerance analysis demonstrates satisfactory robustness. Moreover, we present a polarization-independent converter with slightly modified geometry. The transmittance keeps above 87.2% within the wavelength range from 1500 nm to 1600 nm for both TE and transverse magnetic modes. These devices are expected to contribute to the on-chip mode division multiplexing.

The autostereoscopic 3D display has two important indicators, both the number of viewpoints and display resolution. However, it's a challenge to improve both the viewpoint and the resolution. Here, we develop a fixed-position multiview and lossless resolution autostereoscopic 3D display system that includes the dynamic liquid crystal (LC) grating screen. This display system consists of an LC display panel and an LC grating screen. The synchronization of the frame switching of the LC display panel and the LC grating screen shutter enables the preserved resolution. The "eye space" design makes the viewpoint dense enough and determines the LC grating screen's parameters. Based on the above work, we use binocular viewpoint tracking technology to realize the LC grating screen's adaptive control. Different binocular views are rendered in real-time according to the different positions of a single pair of stereoscopic viewpoints in the eye space, making the motion parallax possible. We present the working principle and mathematical analysis. We implement a prototype for verifying the principle. According to the experiment results analysis, this prototype can achieve viewpoint tracking and motion parallax based on resolution lossless and viewpoint dense enough.

Background Understanding patients’ trust in health information sources is critical to designing work systems in healthcare. Patient-centered communication during the visit might be a major factor in shaping patients’ trust in information sources. Objective The purpose of this paper is to explore relationships between patient ratings of clinician communication during the visit and patient trust in health information sources. Methodology We conducted a secondary analysis of the nationally-representative Health Information National Trends Surveys; HINTS4 Cycle1 (2011), HINTS4 Cycle4 (2014), and HINTS5 Cycle1 (2017), and HINTS5 Cycle2 (2018). We created a composite score of patient-centered communication from five questions and dichotomized at the median. We created multivariable logistic regression models to see how patient-centered communication influenced trust in different information sources across cycles. Consecutively, we used hierarchical analysis for aggregated data. Results We analyzed data from 14,425 individuals. In the adjusted logistic models for each cycle and the hierarchical model, clinicians’ perceived patient-centered communication skills were significantly associated with increased trust in the clinicians as an information source. Conclusion Clinicians still represent an essential source of trustworthy information reinforced by patient-centered communication skills. Given that trust helps build healing relationships that lead to better healthcare outcomes, communication sets an essential foundation to establish necessary trust. Interpreting information from the internet sources for patients is likely to remain a vital clinician function.

Metasurface-based beam splitters with high efficiency, large split angle, wide bandwidth and easy fabrication are highly desirable and still in pursuit. In this paper, we propose a heuristic scheme for designing an ultra-broadband high-efficiency power beam splitter based on a homogeneous metasurface. The conversion efficiency and total transmission intensity of the power splitter stays higher than 95% and 0.66 within the wavelength region from 604 nm to 738 nm, respectively. Particularly, the conversion efficiency can maintain greater than 99% in 58 nm bandwidth. The angle between two split beams can reach a maximum of 157.82° at the wavelength of 738 nm. In addition to simplified design and easy fabrication, the proposed power beam splitter possesses high robustness as well. We expect that our design can pave a new way for realizing high-performance metasurface-based beam splitters.

Conventional metasurfaces cannot adjust the electromagnetic responses once the structures are determined. In this paper, we numerically demonstrate a thermally switchable bifunctional metasurface based on the phase change material vanadium dioxide (VO2) applied to the mid-infrared band. The dual-layer ring resonator consists of an Ag split ring and a VO2 ring, which can achieve ultra-broadband polarization conversion and perfect absorption through the insulator-to-metal phase transition of VO2. When VO2 is in the insulating state, the designed metasurface acts as polarization converter with polarization conversion ratio of over 95% in the wavelength range of 2500 nm to 3500 nm. When VO2 is in the metallic state, the metasurface behaves as perfect absorber with over 90% absorptivity in the region from 2900 nm to 3700 nm. And the operating bandwidths of the two functions are highly overlapped. The ultra-broadband polarization conversion properties are mainly derived from the closed multiple electric and magnetic resonances. Single localized magnetic resonance results in a flat absorption spectrum. The proposed metasurface may provide new ideas for the design of tunable integrated optical devices.

Helix is a multi-year project that aims to develop an understanding of systems engineers and organizational systems engineering (SE) effectiveness. Since 2013, the Helix team has conducted over 180 interview sessions with over 480 individuals from 31 organizations and resulted in over 6,500 pages of text data. As the team continued to gather more interview data, the manual qualitative content analysis methods originally employed was no longer adequate to keep pace with the expanding dataset. In this study, the team proposes a computer assisted method – a multi-level SE analyzer dashboard – to extract, analyze and visualize interview data customized specifically for SE knowledge. The dashboard developed in this study is able to “stay true” to the interviewees’ actual feedback, while automating some aspects of the content analysis to generate useful insights. The multi-level SE analyzer dashboard enables: (1) exploring how critical factors contributing to SE effectiveness in the literature appear in the Helix interviews; (2) comparing SE implementations and processes among various industry sectors; (3) deriving an organizational profile on SE capability; and (4) gathering major concerns and accomplishments from individual systems engineers and senior leadership.

We propose a scheme to realize strong photon antibunching with lower photon nonlinearity in a photonic molecule consisting of two photonic cavities, one of which contains a quantum dot (QD). This strong photon antibunching is attributed to destructive quantum interference effect which suppresses the two-photon excitation of the cavity field. That g^2 (0)~10^(-4) can be achieved with modest QD-cavity coupling strength g=1.1k and cavity tunneling strength J=3k when the system is driven by single laser field. To further reduce the requisite tunneling and make the system tunable, two laser fields are applied to the system. The strong photon antibunching (g^2 (0)~10^(-3)) can be achieved with a relatively large intracavity photon number by optimizing the phase between two driving laser fields when J=0.9k. Moreover, the system shows a strong robustness of maintaining strong photon antibunching within a large parameter variation under the optimal phase condition. Our scheme provides a flexible and efficient method for solid state quantum single photon sources., 9 pages, 7 figures

We propose a design of reciprocal optical diode based on asymmetric spatial mode conversion in multimode silicon waveguide on the silicon-on-insulator platform. The design possesses large bandwidth, high contrast ratio and high fabrication tolerance. The forward even-to-odd mode conversion and backward blockade of even mode are achieved by partial depth etching in the functional region. Simulated by three-dimension finite-difference time-domain method, the forward transmission efficiency is about −2.05 dB while the backward transmission efficiency is only −22.68 dB, reaching a highest contrast ratio of 0.983 at the wavelength of 1550 nm. The operational bandwidth is up to 200 nm (from 1450 nm to 1650 nm) with contrast ratio higher than 0.911. The numerical analysis also demonstrates that the proposed optical diode possesses high tolerance for geometry parameter errors which may be introduced in fabrication. The design based on partial depth etching is compatible with CMOS process and is expected to contribute to the silicon-based all-optical circuits.

Passive cooling, which cools without any electricity input, has had a great impact on global energy consumption. The recent progress on radiative cooling has many potential applications in efficient passive cooling. During the day, this strategy uses the maximized infrared emissivity via the atmospheric transparency windows for radiating heat and minimizing solar absorption. However, the realization of daytime radiative coolers with ideal selective mid-infrared emissivity is still a great challenge. Here, we firstly design and numerically demonstrate a near-ideal radiative cooler operating below the ambient temperature, achieving both broadband selective emissivity in the infrared atmospheric window and extremely low absorption in the entire solar spectrum, realizing a net cooling power exceeding 122 W/m2 at ambient temperature. The cooling effect can still persist under significant nonradiative heat exchange conditions. The design of multi-layer all-dielectric micropyramid structure in this work not only solves the shortcoming of poor mid-infrared selectivity in planar photonics device, but also overcomes the disadvantage of high solar absorption in metal/dielectric metamaterials. The comparisons of physics mechanism between this multi-layer all-dielectric structure and previously reported multi-layer metal/dielectric structure also are investigated clearly. Thus, this study can help pave the way for designing ideal daytime radiative coolers. Keywords: Passive radiative cooling, Thermal radiation, Selective absorption and emission, Microstructures, Broadband perfect absorption

While the use of evidence-based interventions (EBIs) has been advocated by the medical research community for quite some time, uptake of these interventions by healthcare providers has been slow. One possible explanation is that it is challenging for providers to estimate impacts of a specific EBI on their particular organization. To address that concern, we developed and evaluated a type of simulation called a policy flight simulator to determine if it could improve the adoption decision about a specific EBI, the transitional care model (TCM). The TCM uses an advanced practice nurse-led model of care to transition older adults with multiple chronic conditions from a hospitalization to home. An evaluation by a National Advisory Committee, made up of senior representatives from various stakeholders in the U.S. healthcare system, found the policy flight simulator to be a useful tool that has the potential to better inform adoption decisions. This paper describes the simulation development effort and documents lessons learned that may be useful to the healthcare modeling community and those interested in using simulation to support decisions based on EBIs., Convincing clinicians to adopt evidence-based interventions (EBI) has proved challenging. This paper describes the development and evaluation of a "flight simulator" to help clinicians determine the impact of putting a specific EBI into effect in their practices. We document lessons learned that may be useful to the healthcare modeling community and those interested in using simulation to support decisions based on EBIs.

Highly efficient solar absorption is very promising for many practical applications, such as power generation, desalination, wastewater treatment and steam generation. Nevertheless, so far, near-ideal solar thermal energy conversion is still difficult to achieve, which requires a near-perfect absorption from the UV to the near-infrared region and meanwhile a mid-and-far infrared absorption close to zero. Here, by employing FEM and FDTD methods respectively, a nearly omnidirectional ultra-broadband efficient selective solar absorber based on a nanoporous hyperbolic metamaterial (HMM) structure is proposed and numerically demonstrated, which can achieve an extremely high average absorption efficiency above 98.9% within the range of 260–1580 nm. More significantly, in the respect of physical mechanism, the near-perfect solar absorption of this multilayered nanostructures is primarily due to the excitation of magnetic and electric resonances resulting from localized surface plasmon resonance at metal/dielectric interfaces, working completely different from those previously reported tapered multilayered absorbers associated with the slow-light effect. Besides, for retaining heat, a low emissivity is realized in mid-infrared region, causing a near-ideal total solar-thermal conversion efficiency up to 90.32% at 373.15 K (ηideal = 95.6%), which is particularly useful in solar steam generation. Detailed studies are also performed for higher operating temperatures, which indicates efficient solar thermal conversions also can be well maintained by tuning geometric parameters at higher temperatures. Taking into consideration of the practical application, even with ±60 degrees angle of incidence, average absorptivity higher than 90% can be still obtained in the whole solar spectrum at both TE and TM polarization. The near-perfect absorption, wide angle, polarization independence, spectral selectivity and high tunability make this solar absorber promising for practical applications in solar energy harvesting.

Based on the germanium-on-insulator (GeOI) platform, we numerically demonstrate a photonic polarization rotator (PR) operating in the 2 μ m waveband. Utilizing the partial-height etching to break the symmetry of germanium waveguide cross section, the proposed PR realizes a 90° polarization rotation between the fundamental transverse electric (TE) and magnetic (TM) modes. The device footprint occupies only 0.4 μ m × 0 . 4 μ m × 3 μ m. This PR shows a low insertion loss of 0.096 dB, a remarkably high polarization conversion efficiency (PCE) of 98.9%, and an extremely high extinction ratio of 33.45 dB at the wavelength of 2005 nm The PCE keeps above 95.4% within the waveband between 1.9 μ m and 2.1 μ m. Furthermore, a reasonable robustness is demonstrated.

The current consensus is exploring and optimizing the sensing performance of plasmonic transmission structure. The theory used is always trying to reduce the size of the structure, enhance the transmission efficiency, and improve the sensitivity. Here the polarization insensitive transmission and refractive index sensing performance enhanced by staggered metal disk array are investigated at infrared regime. With the metal disks being periodically staggered on both sides of a dielectric layer, there is a great improvement of the transmission efficiency at a specific operating wavelength. Compared with the extraordinary optical transmission on one-dimensional gratings, it is found that the transmission phenomenon is insensitive to the polarization of the incident light. Moreover, the sensing performances at each mode peak are enhanced by the staggered design, and the highest sensitivity reaches more than 5000 nm per refractive index unit (RIU). This work is beneficial for biosensing and extraordinary optical transmission research.

The magneto-optic rotation enhanced by plamonic resonance brought a new method in the research of magnetoplasmon and magneto-optical devices. To further the availability of this method, the Faraday effect on embedded nano-gratings with Bi-substituted yttrium iron garnet substrate is investigated here to achieve bi-directional rotation enhancement selectively. The surface of the simulation structure is designed as 1-D gratings to excite extraordinary optical transmission, and the transmitted light is rotated in the magneto-optic (MO) material. It is found that the characteristic of the bi-directional Faraday rotation enhancement can be greatly influenced by the embedding depth of the metal strips in the MO material. According to this, without changing the applied magnetic field or turning over the MO material, the selectively enhanced Faraday rotation is produced along two opposite directions. Moreover, by optimizing the thickness of metal, a great improvement of figure of merit is obtained. Finally, in the same wavelength regime, the properties of the structure are contrasted when the metal is set to be gold or silver, respectively. This letter provides a useful thought in magnetoplasmon studies, and can be used to fabricate many magneto-optical devices.

We propose a silicon-based asymmetric directional coupler assisted by subwavelength grating anisotropic metamaterial operating at the emerging 2 μm waveband. The effective medium theory is utilized to explain the principle of the proposed structure. Three devices with mode-order conversions are presented. Firstly, TE0-to-TE1, TE0-to-TE2, and TE0-to-TE3 conversions with remarkably high transmittance (>−0.17 dB) and extremely high mode purity (>98.81%) are achieved at the central wavelength of 1985 nm. The fabrication tolerance analyses demonstrate reasonable robustness of the proposed structure. Secondly, such structure can realize a reciprocal optical diode with an exceedingly high contrast ratio (>34 dB) based on spatial symmetry breaking. Finally, we present a symmetric 3 dB mode converter and splitter just by adjusting the length of subwavelength grating and the gap of asymmetric directional coupler. The results reveal that the transmittances of both output ports approach −3 dB around 2 μm and the transmittance difference remains below −10 dB above 40 nm within the waveband from 1.95 μm to 2.05 μm.

We numerically study and analyze the light absorption enhancement in thin crystalline silicon solar cell with dual interface gratings. The structure combines the front dielectric nanowalls and the sinusoidal plasmonic grating at back reflector. We show that having specific interfaces with well-chosen period, fill factor and height can allow more efficient dielectric and plasmonic modes coupling into active layer and can improve the solar cell performance. For 1 µm active layer case, the optimal result for the proposed structure achieves short-circuit current of ~23.6 mA/cm 2 , which performs over 50% better than flat solar cell structure, the short-circuit current of which is ~15.5 mA/cm 2 . In addition, the active layer thickness and angular analysis show that the proposed structure maintains its advantage over flat structure.

We propose and numerically investigate a perfect ultra-narrowband absorber with an absorption bandwidth of only 1.82 nm and an absorption efficiency exceeding 95% in the visible region. We demonstrate that the perfect ultra-narrowband absorption is ascribed to the coupling effect induced by localized surface plasmon resonance. The influence of structural dimensions on the optical performance is also investigated, and the optimal structure is obtained with the extremely low reflectivity (0.001) of the resonance dip. The perfect absorber can be operated as a refractive index sensor with a sensitivity of around 425 nm/RIU and the figure of merit (FOM) reaching 233.5, which greatly improves the accuracy of the plasmonic sensors in visible region. Moreover, the corresponding figure of merit (FOM*) for this sensor is also calculated to describe the performance of the intensity change detection at a fixed frequency, which can be up to 1.4 × 105. Due to the high sensing performance, the metamaterial structure has great potential in the biological binding, integrated photodetectors, chemical applications and so on.

A compact design of all-optical diode with mode conversion function based on a two-dimensional photonic crystal waveguide and an L1 or L3 cavity is theoretically investigated. The proposed photonic crystal structures comprise a triangular arrangement of air holes embedded in a silicon substrate. Asymmetric light propagation is achieved via the spatial mode match/mismatch in the coupling region. The simulations show that at each cavity’s resonance frequency, the transmission efficiency of the structure with the L1 and L3 cavities reach 79% and 73%, while the corresponding unidirectionalities are 46 and 37 dB, respectively. The functional frequency can be controlled by simply adjusting the radii of specific air holes in the L1 and L3 cavities. The proposed structure can be used as a frequency filter, a beam splitter and has potential applications in all-optical integrated circuits.

We propose and investigate a silicon photonic TE-pass polarizer consisting of alternating layers made out of copper/silicon nitride (Cu/Si3N4). Based on a Si stripe waveguide, the launched dominant fundamental TE mode can normally pass through it with little influence, whereas the unwanted fundamental TM mode ends up in nearly zero output as it is gradually coupled into a plasmonic mode. Particularly, the polarizer with wedge-shaped Cu/Si3N4 structure can achieve extremely high extinction ratio (ER) of 52.34 dB and low insertion loss of 0.35 dB within an ultracompact device length of 2 μ m. It also presents a relatively wide operating bandwidth of 61 nm maintaining ER >20 dB. Furthermore, considering Si3N4 itself a good Cu2+ ion diffusion barrier and its good adhesion to copper, the device fabrication is reasonably practicable using complementary metal-oxide semiconductor (CMOS)-compatible technologies. Last but not the least, we first present and analyze the connection between mode property and device performance, which could provide a significant step forward for establishing and improving the polarization diversity systems of great importance in nanophotonic integrated circuits.

We theoretically present a design for simultaneous all-optical or and xor logic gates based on single quantum dot (QD)-bimodal cavity system working in low-photon-number regime. The coupling between the QD and two degenerate cavity modes establishes new indirect excitation paths. Driven by single pulsed laser, both mode transmissions are observed. The delay between the peaks of the transmitted pulses is regarded as the extra transition interval (ETI) in the indirect path. When driven by two orthogonally polarized pulsed lasers with delay same as ETI, the coupling system suppresses the latter mode transmission due to the destructive interference effect. The or and xor logic gates based on presence of light are built and the function can be switched between two detectors by simply adjusting the driving pulse sequence. The results show that the proposed logic gates work well within a large range for coupling strength with comparable cavity decay rate. When taking two nonidealities (the detuning between two cavity modes and nonidentical coupling strengths) into consideration, the proposed system shows acceptable tolerances. Moreover, the robustness of the performance on parameters of the driving lasers, including pulse delay, width of pulse, absolute driving strength, and relative driving strength ratio, are demonstrated.

In this paper, we propose a novel three dimensional metamaterial design with eight-fold rotational symmetry that shows a polarization-insensitive, wide-angle and broadband perfect absorption in the microwave band. By simulation, the polarization-insensitive absorption is over 90% between 26.9 GHz to 32.9 GHz, and the broadband absorption remains a good absorption performance to a wide incident angles for both TE and TM polarizations. The magnetic field distribution are investigated to interpret the physical mechanism of broadband absorption. The broadband absorption is based on overlapping the multiple magnetic resonances at the neighboring frequencies by coupling effects of multiple metallic split-ring resonators (SRRs). Moreover, it is demonstrate that the designed structure can be extended to other frequencies by scale down the size of the unit cell, such as the visible frequencies. The simulated results show that the absorption of the smaller absorber is above 90% in the frequency range from 467 THz to 765 THz(392–642 nm), which include orange to purple light in visible region(400–760nm). The wide-angle and polarization-insensitive stabilities of the smaller absorber is also demonstrated at visible region. The proposed work provides a new design of realization of a polarization-insensitive, wide-angle and broadband absorber ranging different frequency bands, and such a structure has potential application in the fields of solar cell, imaging and detection.

Bragg gratings, because of their favored surface plasmon coupling characteristic, are widely applied in nano-optics. We propose a periodic staggered Bragg gratings structure as a refractive index sensor by the finite element method. The optimized extraordinary optical transmission based on staggered gratings can excite surface plasmon resonance for much larger wavelength. The refractive index can be obtained by detecting the resonant wavelength shift of transmittance peak. This sensor exhibits high sensitivity and favorable linear characteristic in a wide variation interval of refractive index. The simulation results provide a further insight into nano optical sensors.

In the complex space of the healthcare system, we need tools that help decision makers to interactively and inexpensively eliminate infeasible approaches prior to executing expensive changes, and focus on only the most promising strategies. A data-rich agent-based decision support model in the context of hospital consolidation is introduced to address a variety of scenarios. By “rich,” we mean extensive rule sets and information sources: these include agents' financial statements, operational performance, as well as a detailed set of strategic objectives. An application of this model is to analyze hospitals' merger and acquisition activities in New York City based on overarching characteristics for the 5,000+ hospitals nationwide. The model is accompanied by a large-scale interactive visualization, where an array of seven 8′ × 20′, 180 degree touch-screen monitors are installed. This unique approach enables non-technically oriented stakeholders an immersive experience that enables asking many “wha...

Metasurfaces, two-dimensional structures composed of nanoantennas in an array configuration, can be used to fully control electromagnetic waves, which requires a 2π phase shift. Herein, we apply the silicon metasurface as an example to interpret the mechanisms of full 2π phase coverage. It is found that the mechanism varies from Fabry-Perot resonance to Mie resonance as the period increases for a metasurface with certain height. Particularly, there is a transition region between these two types of resonance. We present the corresponding periods and wavelength regions of the different mechanisms when considering the phase-gradient metasurface with at most three diffraction orders. Moreover, the transmission enhancement of metasurface is investigated. The transmission efficiency can be effectively improved when the nanoantenna is changed from a uniform structure to a gradient-index one. We expect that the results can simplify the design process and provide a reference for the future design of all-dielectric metasurface with 2π phase control.

The control of the polarization states of light plays an important role in modern optical systems. However, traditional polarization manipulating devices often have narrow bandwidth and their large size makes it difficult for them to achieve miniaturization and integration of optical systems. This work presents an ultrathin quarter waveplate with a periodic silver film 2 × 2 rectangular hole array with a thickness less than λ/50. Numerical simulation shows that the waveplate can efficiently transform a circular polarized wave into a linearly polarized one at the center of 1550 nm, and its bandwidth is 525 nm. Furthermore, the quarter waveplate can efficiently invert linear polarization into circular polarization at 1550 nm, which ellipticity is near unit. With an array of small holes on a metal film to enhance transmission, this structure can increase the transmission to 0.44. The broadband quarter waveplate can be used in communication system and near infrared band system, and be integrated with other optical devices at nanoscale to achieve polarization operation, detection, and sensing.

A gate-tunable plasmonic optical filter incorporating a subwavelength patterned metal-insulator-metal metasurface heterostructure is proposed. An additional thin transparent conducting oxide (TCO) layer is embedded in the insulator layer to form a double metal-oxide-semiconductor configuration. Heavily n-doped indium tin oxide (ITO) is employed as the TCO material, whose optical property can be electrically tuned by the formation of a thin active epsilon-near-zero layer at the ITO-oxide interfaces. Full-wave electromagnetic simulations show that amplitude modulation and shift of transmission peak are achievable with 3-5 V applied bias, depending on the application. Moreover, the modulation strength and transmission peak shift increase with a thinner ITO layer. This work is an essential step toward a realization of next-generation compact photonic/plasmonic integrated devices.

Given the importance of innovation in economic development, this paper intends to analyze the impacts of multiple factors on innovation efficiency in Zhongguancun Science Park. A two-stage analysis process is implemented. First, data envelopment analysis (DEA) is applied with several inputs and outputs relating to innovation activities. In the second stage, we regressed the efficiency scores from the first stage on the variables of interest. Results show that technological absorptive ability of an industry, external R&D funding by financial organizations and governments, and R&D cooperation among enterprises all positively and significantly affect industry innovation. Besides, it needs to encourage R&D funding by financial organizations as well as control the governmental R&D funding to an appropriate level.

Perfect absorbers play crucial roles in optical functional devices. Among various types of absorbers, moth-eye structures are known for their excellent absorbing efficiency. In this paper, we apply an electromagnetic multipole expansion method to treat an isolated all-dielectric moth-eye structure as a large particle and calculate various electric and magnetic multipole modes within the moth-eye structure. In periodical array, the multipole modes within each particle interact with each other. These constructive or destructive interactions cause shifts in the multipole resonant peaks. The multipole modes inside the particle array introduce reflecting peaks for loss-less materials. The absorption enhancement inside moth-eye structures can be attributed to the electric field enhancement resulting from these electric and magnetic multipole modes. Based on our theoretical study, we propose a near-ideal selective absorber based on moth-eye array, which achieves near 100% absorption within wavelength range from 400 nm to 1500 nm while achieving near 0% absorption over about 1700 nm.

In this paper, we propose an anisotropic dual-band phase gradient metasurface in the infrared region based on tellurium material, which exhibits strong birefringence for z-cut. The refractive index of ordinary light no and extraordinary light ne are along the x- and y-direction of the metasurface, respectively. When a plane wave polarized along the x-direction is normally incident on the metasurface, the diffraction efficiency, which is defined as power of the deflected beam in the desired +1 diffraction order normalized to total transmission power, keeps higher than 95% within the wavelength from 7140nm to 7260nm, meanwhile the total transmission efficiency remains above 78%. On the other hand, the diffraction and total transmission efficiencies keep higher than 95% and 65% within wavelength range from 7840nm to 7940nm for the y-polarized illumination. The metasurface can be applied into polarization splitter, spectral beam splitter, and more in the future.

The Transitional Care Model (TCM) has been rigorously tested in multiple clinical trials but the adoption of this EBI has been one system at a time. The purpose of the first study was to describe key themes important to the decision to adopt the evidence-based interventions (EBIs) and, more specifically, the Transitional Care Model (TCM). A National Advisory Committee (NAC) with representation from providers, payers (public and private) and purchasers were interviewed and transcripts were analyzed using conventional content analyses. Key factors influencing decision making included: 1) the view that “my population” is different; 2) the central role of incentives (specifically payment); 3) beliefs about the value of evidence; and 4) the influence of peers. Factors influencing decision making to adopt EBIs such as the TCM are multidimensional. Understanding the perspectives of decision makers (i.e., providers, payers, and purchasers) is essential to promote adoption of EBIs such as the TCM.

In this paper, we present an all-dielectric gradient metasurface, composed of periodic arrangement of differently sized cross-shaped silicon nanoblocks resting on the fused silica substrate, to realize the function of polarization split in visible region. The cross-shaped silicon block arrays can induce two opposite transmission phase gradients along the x-direction for the linear x-polarization and y-polarization. By properly designing, the metasurface can separate the linearly polarized light into x- and y-polarized ones, which propagate at the same angle along the left and right sides of the normal incidence in the x-z plane. Particularly, when a beam with the polarization angle of 45.0° is incident on the proposed device, the x- and y-polarized transmitted ones possess nearly equal intensity within the wavelength range from 579 to 584 nm. We expect the proposed polarization beam splitter can play an important role for future free-space optical devices.

Background Online medical records are being used to organize processes in clinical and outpatient settings and to forge doctor-patient communication techniques that build mutual understanding and trust. Objective We aimed to understand the reasons why patients tend to avoid using online medical records and to compare the perceptions that patients have of online medical records based on demographics and cancer diagnosis. Methods We used data from the Health Information National Trends Survey Cycle 3, a nationally representative survey, and assessed outcomes using descriptive statistics and chi-square tests. The patients (N=4328) included in the analysis had experienced an outpatient visit within the previous 12 months and had answered the online behavior question regarding their use of online medical records. Results Patients who were nonusers of online medical records consisted of 58.36% of the sample (2526/4328). The highest nonuser rates were for patients who were Hispanic (460/683, 67.35%), patients who were non-Hispanic Black (434/653, 66.46%), and patients who were older than 65 years (968/1520, 63.6%). Patients older than 65 years were less likely to use online medical records (odds ratio [OR] 1.51, 95% CI 1.24-1.84, P Conclusions Studies should consider social factors such as gender, race/ethnicity, and age when monitoring trends in eHealth use to ensure that eHealth use does not induce greater health status and health care disparities between people with different backgrounds and demographic characteristics.

We study the influence of atmospheric turbulence on OAM-based free-space optical (FSO) communication by using the Pump turbulence spectrum model which accurately characterizes the realistic FSO link. A comprehensive comparison is made between the Pump and Kolmogorov spectrum models with respect to the turbulence impact. The calculated results show that obtained turbulence-induced crosstalk is lower, which means that a higher channel capacity is projected when the realistic Pump spectrum is used instead of the Kolmogorov spectrum. We believe that our results prove that performance of practical OAM-based FSO is better than one predicted by using the original Kolmogorov turbulence model.

BACKGROUND Although colorectal cancer (CRC) mortality rates are declining, racial-ethnic disparities in CRC mortality nationally are widening. Herein, the authors attempted to identify county-level variations in this pattern, and to characterize counties with improving disparity trends. METHODS The authors examined 20-year trends in US county-level black-white disparities in CRC age-adjusted mortality rates during the study period between 1989 and 2010. Using a mixed linear model, counties were grouped into mutually exclusive patterns of black-white racial disparity trends in age-adjusted CRC mortality across 20 three-year rolling average data points. County-level characteristics from census data and from the Area Health Resources File were normalized and entered into a principal component analysis. Multinomial logistic regression models were used to test the relation between these factors (clusters of related contextual variables) and the disparity trend pattern group for each county. RESULTS Counties were grouped into 4 disparity trend pattern groups: 1) persistent disparity (parallel black and white trend lines); 2) diverging (widening disparity); 3) sustained equality; and 4) converging (moving from disparate outcomes toward equality). The initial principal component analysis clustered the 82 independent variables into a smaller number of components, 6 of which explained 47% of the county-level variation in disparity trend patterns. CONCLUSIONS County-level variation in social determinants, health care workforce, and health systems all were found to contribute to variations in cancer mortality disparity trend patterns from 1990 through 2010. Counties sustaining equality over time or moving from disparities to equality in cancer mortality suggest that disparities are not inevitable, and provide hope that more communities can achieve optimal and equitable cancer outcomes for all. Cancer 2016;122:1735-48. © 2016 American Cancer Society.

A method of focal-shift resonance with substrate based on two commonly used structures of nano-optical lens is presented with numerical simulations. This resonance exhibits periodicity with the variation of substrate refractive index. Both types of lenses are based on gradual changed nanoslits and analyzed by the extraordinary optical transmission theory. This displacement of focal point can reach the order of microns. A periodic intensity change of focal light is observed between two absorption peaks in metal nanolens. The origin of this focal shift is also discussed with the analysis of the Fresnel number in diffraction. The finite element method is utilized in this paper.

Due to the utilization of overlapped dipole resonances, traditional Huygens’ metasurfaces suffer from dipole interactions. In this Letter, we propose a design of phase-gradient Huygens’ metasurface based on the quadrupole resonances excited in the cross-shaped structures. The quadrupole resonances are theoretically shown insensitive to the quadrupole interactions. Benefiting from this intrinsic property, the proposed metasurface can well suppress element interaction influence and exhibits some impressive properties, including the ability to suppress high diffraction orders, tunable anomalous refractive angles, and high transmission efficiency. The numerical results show promising potential for quadrupole resonances to be applied in advanced Huygens’ metasurface designs.

INTRODUCTION AND OBJECTIVE:We performed this study to investigate the diagnostic performance of PSAD and the optimal cutoff of PSAD in a multicenter cohort of Chinese Prostate Cancer Consortium.MET...

Metasurfaces have pioneered a new avenue for advanced wave-front engineering. Among the various types of metasurfaces, Huygens’ metasurfaces are thought to be a novel paradigm for flat optical devices. Enabled by spectrally overlapped electric resonance and magnetic resonance, Huygens’ metasurfaces are imparted with high transmission and full phase coverage of 2π, which makes them capable of realizing high-efficiency wave-front control. However, a defect of Huygens’ metasurfaces is that their phase profiles and transmissive responses are often sensitive to the interaction of neighboring Huygens’ elements. Consequently, the original assigned phase distribution can be distorted. In this work, we present our design strategy of transmissive Huygens’ metasurfaces performing anomalous refraction. We illustrate the investigation of Huygens’ elements, realizing the overlapping between an electric dipole and magnetic dipole resonance based on cross-shaped structures. We find that the traditional discrete equidistant-phase design method is not enough to realize a transmissive Huygens’ surface due to the interaction between neighboring Huygens’ elements. Therefore, we introduce an extra optimization process on the element spacing to palliate the phase distortion resulting from the element interaction. Based on this method, we successfully design unequally spaced three-element transmissive metasurfaces exhibiting anomalous refraction effect. The anomalous refractive angle of the designed Huygens’ metasurface is 30°, which exceeds the angles of most present transmissive Huygens’ metasurfaces. A transmissive efficiency of 83.5% is numerically derived at the operating wavelength. The far-field electric distribution shows that about 93% of transmissive light is directed along the 30° refractive direction. The deflection angle can be tuned by adjusting the number of Huygens’ elements in one metasurface unit cell. The design strategies used in this paper can be inspiring for other functional Huygens’ metasurface schemes.

The amount of data being digitally collected and stored by health information technology (health IT) is vast and expanding rapidly. How to convert this huge amount of resources into knowledge that can facilitate delivering the right intervention to the right patient, or how to bridge the gap between prevention research and practice, remain unclear. The objective of this study is to develop a Health Service Decision Toolbox (HSDT) that enables healthcare providers to integrate vast data sources collected by Health IT to improve confidence in decisions of whether or not to adopt an evidence-based intervention. HSDT can guide users through feeding massive health related data into several major input groups, such as healthcare providers, patient population, and intervention procedures. With the HSDT, we can successfully project specific impacts, because of additional tailoring to fit each organization/patient population's unique circumstances. When such tailoring combined with an interactive visualization environment, it would further increase decision makers' confidence. We illustrate the use of HSDT with a case study of delivering Transitional Care Model (TCM) to the most needed hospitals. TCM is a proven care management approach that is designed and tested by University of Pennsylvania via multiple NIH funded clinical trials.

High-efficient and high-purity photon sources are highly desired for quantum information processing. We report the design of a chip-scale hybrid SixNy and thin film periodically-poled lithium niobate waveguide for generating high-purity type-II spontaneous parametric down conversion (SPDC) photons in telecommunication band. The modeled second harmonic generation efficiency of 225% W^(-1)*cm^(-2) is obtained at 1560nm. Joint spectral analysis is performed to estimate the frequency correlation of SPDC photons, yielding intrinsic purity with up to 95.17%. The generation rate of these high-purity photon pairs is estimated to be 2.87 * 10^7 pairs/s/mW within the bandwidth of SPDC. Our chip-scale hybrid waveguide design has the potential for large scale on-chip quantum information processing and integrated photon-efficient quantum key distribution through high-dimensional time-energy encoding., 13 pages,7 figures

Plasmonic metasurfaces have attracted much attention in recent years owing to many promising prospects of applications such as polarization switching, local electric field enhancement (FE), near-perfect absorption, sensing, slow-light devices, and nanoantennas. However, many problems in these applications, like only gigahertz switching speeds of electro-optical switches, low-quality factor (Q) of plasmonic resonances, and relatively low figure of merit (FOM) of sensing, severely limit the further development of plasmonic metasurface. Besides, working as nanoantennas, it is also challenging to realize both local electric FE exceeding 100 and near-perfect absorption above 99%. Here, using finite element method and finite difference time domain methods respectively, we firstly report a novel optically tunable plasmonic metasurface based on the hybridization of in-plane near-field coupling and out-of-plane near-field coupling, which provides a good solution to these serious and urgent problems. A physical phenomenon of electromagnetically induced transparency is obtained by the destructive interference between two plasmon modes. At the same time, ultrasharp perfect absorption peaks with ultra-high Q-factor (221.43) is achieved around 1550 nm, which can lead to an ultra-high FOM (214.29) in sensing application. Particularly, by using indium-doped CdO, this metasurface is also firstly demonstrated to be a femtosecond optical reflective polarizer in near-infrared region, possessing an ultra-high polarization extinction ratio. Meanwhile, operating as nanoantennas, this metasurface achieves simultaneously strong local electric FE(|E loc|/|E 0| > 100) and a near-perfect absorption above 99.9% for the first time, which will benefit a wide range of applications including photocatalytic water splitting and surface-enhanced infrared absorption.

We propose and numerically demonstrate an ultra-broadband graphene-based metamaterial absorber, which consists of multi-layer graphene/dielectric on the SiO2 layer supported by a metal substrate. The simulated result shows that the proposed absorber can achieve a near-perfect absorption above 90% with a bandwidth of 4.8 Thz. Owing to the flexible tunability of graphene sheet, the state of the absorber can be switched from on (absorption > 90%) to off (reflection > 90%) in the frequencies range of 3–7.8 Thz by controlling the Fermi energy of graphene. Moreover, the absorber is insensitive to the incident angles. The broadband absorption can be maintained over 90% up to 50°. Importantly, the design is scalable to develop broader tunable terahertz absorbers by adding more graphene layers which may have wide applications in imaging, sensors, photodetectors, and modulators.